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3 @c under the terms of the GNU Free Documentation License, Version 1.3 or
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7 @c and with the Back-Cover Texts as in (a) below.
9 @c (a) The FSF's Back-Cover Text is: ``You are free to copy and modify
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14 @section Extending @value{GDBN} using Guile
15 @cindex guile scripting
16 @cindex scripting with guile
18 You can extend @value{GDBN} using the @uref{http://www.gnu.org/software/guile/,
19 Guile implementation of the Scheme programming language}.
20 This feature is available only if @value{GDBN} was configured using
21 @option{--with-guile}.
24 * Guile Introduction:: Introduction to Guile scripting in @value{GDBN}
25 * Guile Commands:: Accessing Guile from @value{GDBN}
26 * Guile API:: Accessing @value{GDBN} from Guile
27 * Guile Auto-loading:: Automatically loading Guile code
28 * Guile Modules:: Guile modules provided by @value{GDBN}
31 @node Guile Introduction
32 @subsection Guile Introduction
34 Guile is an implementation of the Scheme programming language
35 and is the GNU project's official extension language.
37 Guile support in @value{GDBN} follows the Python support in @value{GDBN}
38 reasonably closely, so concepts there should carry over.
39 However, some things are done differently where it makes sense.
41 @value{GDBN} requires Guile version 2.0 or greater.
42 Older versions are not supported.
44 @cindex guile scripts directory
45 Guile scripts used by @value{GDBN} should be installed in
46 @file{@var{data-directory}/guile}, where @var{data-directory} is
47 the data directory as determined at @value{GDBN} startup (@pxref{Data Files}).
48 This directory, known as the @dfn{guile directory},
49 is automatically added to the Guile Search Path in order to allow
50 the Guile interpreter to locate all scripts installed at this location.
53 @subsection Guile Commands
54 @cindex guile commands
55 @cindex commands to access guile
57 @value{GDBN} provides two commands for accessing the Guile interpreter:
64 The @code{guile-repl} command can be used to start an interactive
65 Guile prompt or @dfn{repl}. To return to @value{GDBN},
66 type @kbd{,q} or the @code{EOF} character (e.g., @kbd{Ctrl-D} on
67 an empty prompt). These commands do not take any arguments.
71 @item guile @r{[}@var{scheme-expression}@r{]}
72 @itemx gu @r{[}@var{scheme-expression}@r{]}
73 The @code{guile} command can be used to evaluate a Scheme expression.
75 If given an argument, @value{GDBN} will pass the argument to the Guile
76 interpreter for evaluation.
79 (@value{GDBP}) guile (display (+ 20 3)) (newline)
83 The result of the Scheme expression is displayed using normal Guile rules.
86 (@value{GDBP}) guile (+ 20 3)
90 If you do not provide an argument to @code{guile}, it will act as a
91 multi-line command, like @code{define}. In this case, the Guile
92 script is made up of subsequent command lines, given after the
93 @code{guile} command. This command list is terminated using a line
94 containing @code{end}. For example:
105 It is also possible to execute a Guile script from the @value{GDBN}
109 @item source @file{script-name}
110 The script name must end with @samp{.scm} and @value{GDBN} must be configured
111 to recognize the script language based on filename extension using
112 the @code{script-extension} setting. @xref{Extending GDB, ,Extending GDB}.
114 @item guile (load "script-name")
115 This method uses the @code{load} Guile function.
116 It takes a string argument that is the name of the script to load.
117 See the Guile documentation for a description of this function.
118 (@pxref{Loading,,, guile, GNU Guile Reference Manual}).
122 @subsection Guile API
124 @cindex programming in guile
126 You can get quick online help for @value{GDBN}'s Guile API by issuing
127 the command @w{@kbd{help guile}}, or by issuing the command @kbd{,help}
128 from an interactive Guile session. Furthermore, most Guile procedures
129 provided by @value{GDBN} have doc strings which can be obtained with
130 @kbd{,describe @var{procedure-name}} or @kbd{,d @var{procedure-name}}
131 from the Guile interactive prompt.
134 * Basic Guile:: Basic Guile Functions
135 * Guile Configuration:: Guile configuration variables
136 * GDB Scheme Data Types:: Scheme representations of GDB objects
137 * Guile Exception Handling:: How Guile exceptions are translated
138 * Values From Inferior In Guile:: Guile representation of values
139 * Arithmetic In Guile:: Arithmetic in Guile
140 * Types In Guile:: Guile representation of types
141 * Guile Pretty Printing API:: Pretty-printing values with Guile
142 * Selecting Guile Pretty-Printers:: How GDB chooses a pretty-printer
143 * Writing a Guile Pretty-Printer:: Writing a pretty-printer
144 * Commands In Guile:: Implementing new commands in Guile
145 * Parameters In Guile:: Adding new @value{GDBN} parameters
146 * Progspaces In Guile:: Program spaces
147 * Objfiles In Guile:: Object files in Guile
148 * Frames In Guile:: Accessing inferior stack frames from Guile
149 * Blocks In Guile:: Accessing blocks from Guile
150 * Symbols In Guile:: Guile representation of symbols
151 * Symbol Tables In Guile:: Guile representation of symbol tables
152 * Breakpoints In Guile:: Manipulating breakpoints using Guile
153 * Lazy Strings In Guile:: Guile representation of lazy strings
154 * Architectures In Guile:: Guile representation of architectures
155 * Disassembly In Guile:: Disassembling instructions from Guile
156 * I/O Ports in Guile:: GDB I/O ports
157 * Memory Ports in Guile:: Accessing memory through ports and bytevectors
158 * Iterators In Guile:: Basic iterator support
162 @subsubsection Basic Guile
165 @cindex guile pagination
166 At startup, @value{GDBN} overrides Guile's @code{current-output-port} and
167 @code{current-error-port} to print using @value{GDBN}'s output-paging streams.
168 A Guile program which outputs to one of these streams may have its
169 output interrupted by the user (@pxref{Screen Size}). In this
170 situation, a Guile @code{signal} exception is thrown with value @code{SIGINT}.
172 Guile's history mechanism uses the same naming as @value{GDBN}'s,
173 namely the user of dollar-variables (e.g., $1, $2, etc.).
174 The results of evaluations in Guile and in GDB are counted separately,
175 @code{$1} in Guile is not the same value as @code{$1} in @value{GDBN}.
177 @value{GDBN} is not thread-safe. If your Guile program uses multiple
178 threads, you must be careful to only call @value{GDBN}-specific
179 functions in the @value{GDBN} thread.
181 Some care must be taken when writing Guile code to run in
182 @value{GDBN}. Two things are worth noting in particular:
186 @value{GDBN} installs handlers for @code{SIGCHLD} and @code{SIGINT}.
187 Guile code must not override these, or even change the options using
188 @code{sigaction}. If your program changes the handling of these
189 signals, @value{GDBN} will most likely stop working correctly. Note
190 that it is unfortunately common for GUI toolkits to install a
191 @code{SIGCHLD} handler.
194 @value{GDBN} takes care to mark its internal file descriptors as
195 close-on-exec. However, this cannot be done in a thread-safe way on
196 all platforms. Your Guile programs should be aware of this and
197 should both create new file descriptors with the close-on-exec flag
198 set and arrange to close unneeded file descriptors before starting a
202 @cindex guile gdb module
203 @value{GDBN} introduces a new Guile module, named @code{gdb}. All
204 methods and classes added by @value{GDBN} are placed in this module.
205 @value{GDBN} does not automatically @code{import} the @code{gdb} module,
206 scripts must do this themselves. There are various options for how to
207 import a module, so @value{GDBN} leaves the choice of how the @code{gdb}
208 module is imported to the user.
209 To simplify interactive use, it is recommended to add one of the following
213 guile (use-modules (gdb))
217 guile (use-modules ((gdb) #:renamer (symbol-prefix-proc 'gdb:)))
220 Which one to choose depends on your preference.
221 The second one adds @code{gdb:} as a prefix to all module functions
224 The rest of this manual assumes the @code{gdb} module has been imported
225 without any prefix. See the Guile documentation for @code{use-modules}
227 (@pxref{Using Guile Modules,,, guile, GNU Guile Reference Manual}).
232 (gdb) guile (value-type (make-value 1))
233 ERROR: Unbound variable: value-type
234 Error while executing Scheme code.
235 (gdb) guile (use-modules (gdb))
236 (gdb) guile (value-type (make-value 1))
241 The @code{(gdb)} module provides these basic Guile functions.
244 @deffn {Scheme Procedure} execute command @r{[}#:from-tty boolean@r{]} @r{[}#:to-string boolean@r{]}
245 Evaluate @var{command}, a string, as a @value{GDBN} CLI command.
246 If a @value{GDBN} exception happens while @var{command} runs, it is
247 translated as described in
248 @ref{Guile Exception Handling,,Guile Exception Handling}.
250 @var{from-tty} specifies whether @value{GDBN} ought to consider this
251 command as having originated from the user invoking it interactively.
252 It must be a boolean value. If omitted, it defaults to @code{#f}.
254 By default, any output produced by @var{command} is sent to
255 @value{GDBN}'s standard output (and to the log output if logging is
256 turned on). If the @var{to-string} parameter is
257 @code{#t}, then output will be collected by @code{execute} and
258 returned as a string. The default is @code{#f}, in which case the
259 return value is unspecified. If @var{to-string} is @code{#t}, the
260 @value{GDBN} virtual terminal will be temporarily set to unlimited width
261 and height, and its pagination will be disabled; @pxref{Screen Size}.
264 @deffn {Scheme Procedure} history-ref number
265 Return a value from @value{GDBN}'s value history (@pxref{Value
266 History}). The @var{number} argument indicates which history element to return.
267 If @var{number} is negative, then @value{GDBN} will take its absolute value
268 and count backward from the last element (i.e., the most recent element) to
269 find the value to return. If @var{number} is zero, then @value{GDBN} will
270 return the most recent element. If the element specified by @var{number}
271 doesn't exist in the value history, a @code{gdb:error} exception will be
274 If no exception is raised, the return value is always an instance of
275 @code{<gdb:value>} (@pxref{Values From Inferior In Guile}).
277 @emph{Note:} @value{GDBN}'s value history is independent of Guile's.
278 @code{$1} in @value{GDBN}'s value history contains the result of evaluating
279 an expression from @value{GDBN}'s command line and @code{$1} from Guile's
280 history contains the result of evaluating an expression from Guile's
284 @deffn {Scheme Procedure} history-append! value
285 Append @var{value}, an instance of @code{<gdb:value>}, to @value{GDBN}'s
286 value history. Return its index in the history.
288 Putting into history values returned by Guile extensions will allow
289 the user convenient access to those values via CLI history
293 @deffn {Scheme Procedure} parse-and-eval expression
294 Parse @var{expression} as an expression in the current language,
295 evaluate it, and return the result as a @code{<gdb:value>}.
296 The @var{expression} must be a string.
298 This function can be useful when implementing a new command
299 (@pxref{Commands In Guile}), as it provides a way to parse the
300 command's arguments as an expression.
301 It is also is useful when computing values.
302 For example, it is the only way to get the value of a
303 convenience variable (@pxref{Convenience Vars}) as a @code{<gdb:value>}.
306 @node Guile Configuration
307 @subsubsection Guile Configuration
308 @cindex guile configuration
310 @value{GDBN} provides these Scheme functions to access various configuration
313 @deffn {Scheme Procedure} data-directory
314 Return a string containing @value{GDBN}'s data directory.
315 This directory contains @value{GDBN}'s ancillary files, including
316 the Guile modules provided by @value{GDBN}.
319 @deffn {Scheme Procedure} gdb-version
320 Return a string containing the @value{GDBN} version.
323 @deffn {Scheme Procedure} host-config
324 Return a string containing the host configuration.
325 This is the string passed to @code{--host} when @value{GDBN} was configured.
328 @deffn {Scheme Procedure} target-config
329 Return a string containing the target configuration.
330 This is the string passed to @code{--target} when @value{GDBN} was configured.
333 @node GDB Scheme Data Types
334 @subsubsection GDB Scheme Data Types
337 The values exposed by @value{GDBN} to Guile are known as
338 @dfn{@value{GDBN} objects}. There are several kinds of @value{GDBN}
339 object, and each is disjoint from all other types known to Guile.
341 @deffn {Scheme Procedure} gdb-object-kind object
342 Return the kind of the @value{GDBN} object, e.g., @code{<gdb:breakpoint>},
346 @value{GDBN} defines the following object types:
350 @xref{Architectures In Guile}.
353 @xref{Blocks In Guile}.
355 @item <gdb:block-symbols-iterator>
356 @xref{Blocks In Guile}.
358 @item <gdb:breakpoint>
359 @xref{Breakpoints In Guile}.
362 @xref{Commands In Guile}.
364 @item <gdb:exception>
365 @xref{Guile Exception Handling}.
368 @xref{Frames In Guile}.
371 @xref{Iterators In Guile}.
373 @item <gdb:lazy-string>
374 @xref{Lazy Strings In Guile}.
377 @xref{Objfiles In Guile}.
379 @item <gdb:parameter>
380 @xref{Parameters In Guile}.
382 @item <gdb:pretty-printer>
383 @xref{Guile Pretty Printing API}.
385 @item <gdb:pretty-printer-worker>
386 @xref{Guile Pretty Printing API}.
388 @item <gdb:progspace>
389 @xref{Progspaces In Guile}.
392 @xref{Symbols In Guile}.
395 @xref{Symbol Tables In Guile}.
398 @xref{Symbol Tables In Guile}.
401 @xref{Types In Guile}.
404 @xref{Types In Guile}.
407 @xref{Values From Inferior In Guile}.
410 The following @value{GDBN} objects are managed internally so that the
411 Scheme function @code{eq?} may be applied to them.
416 @item <gdb:breakpoint>
419 @item <gdb:progspace>
425 @node Guile Exception Handling
426 @subsubsection Guile Exception Handling
427 @cindex guile exceptions
428 @cindex exceptions, guile
429 @kindex set guile print-stack
431 When executing the @code{guile} command, Guile exceptions
432 uncaught within the Guile code are translated to calls to the
433 @value{GDBN} error-reporting mechanism. If the command that called
434 @code{guile} does not handle the error, @value{GDBN} will
435 terminate it and report the error according to the setting of
436 the @code{guile print-stack} parameter.
438 The @code{guile print-stack} parameter has three settings:
445 An error message is printed containing the Guile exception name,
446 the associated value, and the Guile call stack backtrace at the
447 point where the exception was raised. Example:
450 (@value{GDBP}) guile (display foo)
451 ERROR: In procedure memoize-variable-access!:
452 ERROR: Unbound variable: foo
453 Error while executing Scheme code.
457 In addition to an error message a full backtrace is printed.
460 (@value{GDBP}) set guile print-stack full
461 (@value{GDBP}) guile (display foo)
464 157: 10 [catch #t #<catch-closure 2c76e20> ...]
466 ?: 9 [apply-smob/1 #<catch-closure 2c76e20>]
468 157: 8 [catch #t #<catch-closure 2c76d20> ...]
470 ?: 7 [apply-smob/1 #<catch-closure 2c76d20>]
471 ?: 6 [call-with-input-string "(display foo)" ...]
473 2320: 5 [save-module-excursion #<procedure 2c2dc30 ... ()>]
474 In ice-9/eval-string.scm:
475 44: 4 [read-and-eval #<input: string 27cb410> #:lang ...]
476 37: 3 [lp (display foo)]
479 393: 1 [eval #<memoized foo> ()]
481 ?: 0 [memoize-variable-access! #<memoized foo> ...]
483 ERROR: In procedure memoize-variable-access!:
484 ERROR: Unbound variable: foo
485 Error while executing Scheme code.
489 @value{GDBN} errors that happen in @value{GDBN} commands invoked by
490 Guile code are converted to Guile exceptions. The type of the
491 Guile exception depends on the error.
493 Guile procedures provided by @value{GDBN} can throw the standard
494 Guile exceptions like @code{wrong-type-arg} and @code{out-of-range}.
496 User interrupt (via @kbd{C-c} or by typing @kbd{q} at a pagination
497 prompt) is translated to a Guile @code{signal} exception with value
500 @value{GDBN} Guile procedures can also throw these exceptions:
504 This exception is a catch-all for errors generated from within @value{GDBN}.
506 @item gdb:invalid-object
507 This exception is thrown when accessing Guile objects that wrap underlying
508 @value{GDBN} objects have become invalid. For example, a
509 @code{<gdb:breakpoint>} object becomes invalid if the user deletes it
510 from the command line. The object still exists in Guile, but the
511 object it represents is gone. Further operations on this breakpoint
512 will throw this exception.
514 @item gdb:memory-error
515 This exception is thrown when an operation tried to access invalid
516 memory in the inferior.
518 @item gdb:pp-type-error
519 This exception is thrown when a Guile pretty-printer passes a bad object
523 The following exception-related procedures are provided by the
526 @deffn {Scheme Procedure} make-exception key args
527 Return a @code{<gdb:exception>} object given by its @var{key} and
528 @var{args}, which are the standard Guile parameters of an exception.
529 See the Guile documentation for more information (@pxref{Exceptions,,,
530 guile, GNU Guile Reference Manual}).
533 @deffn {Scheme Procedure} exception? object
534 Return @code{#t} if @var{object} is a @code{<gdb:exception>} object.
535 Otherwise return @code{#f}.
538 @deffn {Scheme Procedure} exception-key exception
539 Return the @var{args} field of a @code{<gdb:exception>} object.
542 @deffn {Scheme Procedure} exception-args exception
543 Return the @var{args} field of a @code{<gdb:exception>} object.
546 @node Values From Inferior In Guile
547 @subsubsection Values From Inferior In Guile
548 @cindex values from inferior, in guile
549 @cindex guile, working with values from inferior
551 @tindex @code{<gdb:value>}
552 @value{GDBN} provides values it obtains from the inferior program in
553 an object of type @code{<gdb:value>}. @value{GDBN} uses this object
554 for its internal bookkeeping of the inferior's values, and for
555 fetching values when necessary.
557 @value{GDBN} does not memoize @code{<gdb:value>} objects.
558 @code{make-value} always returns a fresh object.
561 (gdb) guile (eq? (make-value 1) (make-value 1))
563 (gdb) guile (equal? (make-value 1) (make-value 1))
567 A @code{<gdb:value>} that represents a function can be executed via
568 inferior function call with @code{value-call}.
569 Any arguments provided to the call must match the function's prototype,
570 and must be provided in the order specified by that prototype.
572 For example, @code{some-val} is a @code{<gdb:value>} instance
573 representing a function that takes two integers as arguments. To
574 execute this function, call it like so:
577 (define result (value-call some-val 10 20))
580 Any values returned from a function call are @code{<gdb:value>} objects.
582 Note: Unlike Python scripting in @value{GDBN},
583 inferior values that are simple scalars cannot be used directly in
584 Scheme expressions that are valid for the value's data type.
585 For example, @code{(+ (parse-and-eval "int_variable") 2)} does not work.
586 And inferior values that are structures or instances of some class cannot
587 be accessed using any special syntax, instead @code{value-field} must be used.
589 The following value-related procedures are provided by the
592 @deffn {Scheme Procedure} value? object
593 Return @code{#t} if @var{object} is a @code{<gdb:value>} object.
594 Otherwise return @code{#f}.
597 @deffn {Scheme Procedure} make-value value @r{[}#:type type@r{]}
598 Many Scheme values can be converted directly to a @code{<gdb:value>}
599 with this procedure. If @var{type} is specified, the result is a value
600 of this type, and if @var{value} can't be represented with this type
601 an exception is thrown. Otherwise the type of the result is determined from
602 @var{value} as described below.
604 @xref{Architectures In Guile}, for a list of the builtin
605 types for an architecture.
607 Here's how Scheme values are converted when @var{type} argument to
608 @code{make-value} is not specified:
612 A Scheme boolean is converted the boolean type for the current language.
615 A Scheme integer is converted to the first of a C @code{int},
616 @code{unsigned int}, @code{long}, @code{unsigned long},
617 @code{long long} or @code{unsigned long long} type
618 for the current architecture that can represent the value.
620 If the Scheme integer cannot be represented as a target integer
621 an @code{out-of-range} exception is thrown.
624 A Scheme real is converted to the C @code{double} type for the
625 current architecture.
628 A Scheme string is converted to a string in the current target
629 language using the current target encoding.
630 Characters that cannot be represented in the current target encoding
631 are replaced with the corresponding escape sequence. This is Guile's
632 @code{SCM_FAILED_CONVERSION_ESCAPE_SEQUENCE} conversion strategy
633 (@pxref{Strings,,, guile, GNU Guile Reference Manual}).
635 Passing @var{type} is not supported in this case,
636 if it is provided a @code{wrong-type-arg} exception is thrown.
638 @item @code{<gdb:lazy-string>}
639 If @var{value} is a @code{<gdb:lazy-string>} object (@pxref{Lazy Strings In
640 Guile}), then the @code{lazy-string->value} procedure is called, and
643 Passing @var{type} is not supported in this case,
644 if it is provided a @code{wrong-type-arg} exception is thrown.
646 @item Scheme bytevector
647 If @var{value} is a Scheme bytevector and @var{type} is provided,
648 @var{value} must be the same size, in bytes, of values of type @var{type},
649 and the result is essentially created by using @code{memcpy}.
651 If @var{value} is a Scheme bytevector and @var{type} is not provided,
652 the result is an array of type @code{uint8} of the same length.
656 @cindex optimized out value in guile
657 @deffn {Scheme Procedure} value-optimized-out? value
658 Return @code{#t} if the compiler optimized out @var{value},
659 thus it is not available for fetching from the inferior.
660 Otherwise return @code{#f}.
663 @deffn {Scheme Procedure} value-address value
664 If @var{value} is addressable, returns a
665 @code{<gdb:value>} object representing the address.
666 Otherwise, @code{#f} is returned.
669 @deffn {Scheme Procedure} value-type value
670 Return the type of @var{value} as a @code{<gdb:type>} object
671 (@pxref{Types In Guile}).
674 @deffn {Scheme Procedure} value-dynamic-type value
675 Return the dynamic type of @var{value}. This uses C@t{++} run-time
676 type information (@acronym{RTTI}) to determine the dynamic type of the
677 value. If the value is of class type, it will return the class in
678 which the value is embedded, if any. If the value is of pointer or
679 reference to a class type, it will compute the dynamic type of the
680 referenced object, and return a pointer or reference to that type,
681 respectively. In all other cases, it will return the value's static
684 Note that this feature will only work when debugging a C@t{++} program
685 that includes @acronym{RTTI} for the object in question. Otherwise,
686 it will just return the static type of the value as in @kbd{ptype foo}.
687 @xref{Symbols, ptype}.
690 @deffn {Scheme Procedure} value-cast value type
691 Return a new instance of @code{<gdb:value>} that is the result of
692 casting @var{value} to the type described by @var{type}, which must
693 be a @code{<gdb:type>} object. If the cast cannot be performed for some
694 reason, this method throws an exception.
697 @deffn {Scheme Procedure} value-dynamic-cast value type
698 Like @code{value-cast}, but works as if the C@t{++} @code{dynamic_cast}
699 operator were used. Consult a C@t{++} reference for details.
702 @deffn {Scheme Procedure} value-reinterpret-cast value type
703 Like @code{value-cast}, but works as if the C@t{++} @code{reinterpret_cast}
704 operator were used. Consult a C@t{++} reference for details.
707 @deffn {Scheme Procedure} value-dereference value
708 For pointer data types, this method returns a new @code{<gdb:value>} object
709 whose contents is the object pointed to by @var{value}. For example, if
710 @code{foo} is a C pointer to an @code{int}, declared in your C program as
717 then you can use the corresponding @code{<gdb:value>} to access what
718 @code{foo} points to like this:
721 (define bar (value-dereference foo))
724 The result @code{bar} will be a @code{<gdb:value>} object holding the
725 value pointed to by @code{foo}.
727 A similar function @code{value-referenced-value} exists which also
728 returns @code{<gdb:value>} objects corresonding to the values pointed to
729 by pointer values (and additionally, values referenced by reference
730 values). However, the behavior of @code{value-dereference}
731 differs from @code{value-referenced-value} by the fact that the
732 behavior of @code{value-dereference} is identical to applying the C
733 unary operator @code{*} on a given value. For example, consider a
734 reference to a pointer @code{ptrref}, declared in your C@t{++} program
742 intptr &ptrref = ptr;
745 Though @code{ptrref} is a reference value, one can apply the method
746 @code{value-dereference} to the @code{<gdb:value>} object corresponding
747 to it and obtain a @code{<gdb:value>} which is identical to that
748 corresponding to @code{val}. However, if you apply the method
749 @code{value-referenced-value}, the result would be a @code{<gdb:value>}
750 object identical to that corresponding to @code{ptr}.
753 (define scm-ptrref (parse-and-eval "ptrref"))
754 (define scm-val (value-dereference scm-ptrref))
755 (define scm-ptr (value-referenced-value scm-ptrref))
758 The @code{<gdb:value>} object @code{scm-val} is identical to that
759 corresponding to @code{val}, and @code{scm-ptr} is identical to that
760 corresponding to @code{ptr}. In general, @code{value-dereference} can
761 be applied whenever the C unary operator @code{*} can be applied
762 to the corresponding C value. For those cases where applying both
763 @code{value-dereference} and @code{value-referenced-value} is allowed,
764 the results obtained need not be identical (as we have seen in the above
765 example). The results are however identical when applied on
766 @code{<gdb:value>} objects corresponding to pointers (@code{<gdb:value>}
767 objects with type code @code{TYPE_CODE_PTR}) in a C/C@t{++} program.
770 @deffn {Scheme Procedure} value-referenced-value value
771 For pointer or reference data types, this method returns a new
772 @code{<gdb:value>} object corresponding to the value referenced by the
773 pointer/reference value. For pointer data types,
774 @code{value-dereference} and @code{value-referenced-value} produce
775 identical results. The difference between these methods is that
776 @code{value-dereference} cannot get the values referenced by reference
777 values. For example, consider a reference to an @code{int}, declared
778 in your C@t{++} program as
786 then applying @code{value-dereference} to the @code{<gdb:value>} object
787 corresponding to @code{ref} will result in an error, while applying
788 @code{value-referenced-value} will result in a @code{<gdb:value>} object
789 identical to that corresponding to @code{val}.
792 (define scm-ref (parse-and-eval "ref"))
793 (define err-ref (value-dereference scm-ref)) ;; error
794 (define scm-val (value-referenced-value scm-ref)) ;; ok
797 The @code{<gdb:value>} object @code{scm-val} is identical to that
798 corresponding to @code{val}.
801 @deffn {Scheme Procedure} value-field value field-name
802 Return field @var{field-name} from @code{<gdb:value>} object @var{value}.
805 @deffn {Scheme Procedure} value-subscript value index
806 Return the value of array @var{value} at index @var{index}.
807 The @var{value} argument must be a subscriptable @code{<gdb:value>} object.
810 @deffn {Scheme Procedure} value-call value arg-list
811 Perform an inferior function call, taking @var{value} as a pointer
812 to the function to call.
813 Each element of list @var{arg-list} must be a <gdb:value> object or an object
814 that can be converted to a value.
815 The result is the value returned by the function.
818 @deffn {Scheme Procedure} value->bool value
819 Return the Scheme boolean representing @code{<gdb:value>} @var{value}.
820 The value must be ``integer like''. Pointers are ok.
823 @deffn {Scheme Procedure} value->integer
824 Return the Scheme integer representing @code{<gdb:value>} @var{value}.
825 The value must be ``integer like''. Pointers are ok.
828 @deffn {Scheme Procedure} value->real
829 Return the Scheme real number representing @code{<gdb:value>} @var{value}.
830 The value must be a number.
833 @deffn {Scheme Procedure} value->bytevector
834 Return a Scheme bytevector with the raw contents of @code{<gdb:value>}
835 @var{value}. No transformation, endian or otherwise, is performed.
839 @deffn {Scheme Procedure} value->string value @r{[}#:encoding encoding@r{]} @r{[}#:errors errors@r{]} @r{[}#:length length@r{]}
840 If @var{value>} represents a string, then this method
841 converts the contents to a Guile string. Otherwise, this method will
844 Values are interpreted as strings according to the rules of the
845 current language. If the optional length argument is given, the
846 string will be converted to that length, and will include any embedded
847 zeroes that the string may contain. Otherwise, for languages
848 where the string is zero-terminated, the entire string will be
851 For example, in C-like languages, a value is a string if it is a pointer
852 to or an array of characters or ints of type @code{wchar_t}, @code{char16_t},
855 If the optional @var{encoding} argument is given, it must be a string
856 naming the encoding of the string in the @code{<gdb:value>}, such as
857 @code{"ascii"}, @code{"iso-8859-6"} or @code{"utf-8"}. It accepts
858 the same encodings as the corresponding argument to Guile's
859 @code{scm_from_stringn} function, and the Guile codec machinery will be used
860 to convert the string. If @var{encoding} is not given, or if
861 @var{encoding} is the empty string, then either the @code{target-charset}
862 (@pxref{Character Sets}) will be used, or a language-specific encoding
863 will be used, if the current language is able to supply one.
865 The optional @var{errors} argument is one of @code{#f}, @code{error} or
866 @code{substitute}. @code{error} and @code{substitute} must be symbols.
867 If @var{errors} is not specified, or if its value is @code{#f}, then the
868 default conversion strategy is used, which is set with the Scheme function
869 @code{set-port-conversion-strategy!}.
870 If the value is @code{'error} then an exception is thrown if there is any
871 conversion error. If the value is @code{'substitute} then any conversion
872 error is replaced with question marks.
873 @xref{Strings,,, guile, GNU Guile Reference Manual}.
875 If the optional @var{length} argument is given, the string will be
876 fetched and converted to the given length.
877 The length must be a Scheme integer and not a @code{<gdb:value>} integer.
881 @deffn {Scheme Procedure} value->lazy-string value @r{[}#:encoding encoding@r{]} @r{[}#:length length@r{]}
882 If this @code{<gdb:value>} represents a string, then this method
883 converts @var{value} to a @code{<gdb:lazy-string} (@pxref{Lazy Strings
884 In Guile}). Otherwise, this method will throw an exception.
886 If the optional @var{encoding} argument is given, it must be a string
887 naming the encoding of the @code{<gdb:lazy-string}. Some examples are:
888 @code{"ascii"}, @code{"iso-8859-6"} or @code{"utf-8"}. If the
889 @var{encoding} argument is an encoding that @value{GDBN} does not
890 recognize, @value{GDBN} will raise an error.
892 When a lazy string is printed, the @value{GDBN} encoding machinery is
893 used to convert the string during printing. If the optional
894 @var{encoding} argument is not provided, or is an empty string,
895 @value{GDBN} will automatically select the encoding most suitable for
896 the string type. For further information on encoding in @value{GDBN}
897 please see @ref{Character Sets}.
899 If the optional @var{length} argument is given, the string will be
900 fetched and encoded to the length of characters specified. If
901 the @var{length} argument is not provided, the string will be fetched
902 and encoded until a null of appropriate width is found.
903 The length must be a Scheme integer and not a @code{<gdb:value>} integer.
906 @deffn {Scheme Procedure} value-lazy? value
907 Return @code{#t} if @var{value} has not yet been fetched
909 Otherwise return @code{#f}.
910 @value{GDBN} does not fetch values until necessary, for efficiency.
914 (define myval (parse-and-eval "somevar"))
917 The value of @code{somevar} is not fetched at this time. It will be
918 fetched when the value is needed, or when the @code{fetch-lazy}
919 procedure is invoked.
922 @deffn {Scheme Procedure} make-lazy-value type address
923 Return a @code{<gdb:value>} that will be lazily fetched from the
924 target. The object of type @code{<gdb:type>} whose value to fetch is
925 specified by its @var{type} and its target memory @var{address}, which
929 @deffn {Scheme Procedure} value-fetch-lazy! value
930 If @var{value} is a lazy value (@code{(value-lazy? value)} is @code{#t}),
931 then the value is fetched from the inferior.
932 Any errors that occur in the process will produce a Guile exception.
934 If @var{value} is not a lazy value, this method has no effect.
936 The result of this function is unspecified.
939 @deffn {Scheme Procedure} value-print value
940 Return the string representation (print form) of @code{<gdb:value>}
944 @node Arithmetic In Guile
945 @subsubsection Arithmetic In Guile
947 The @code{(gdb)} module provides several functions for performing
948 arithmetic on @code{<gdb:value>} objects.
949 The arithmetic is performed as if it were done by the target,
950 and therefore has target semantics which are not necessarily
951 those of Scheme. For example operations work with a fixed precision,
952 not the arbitrary precision of Scheme.
954 Wherever a function takes an integer or pointer as an operand,
955 @value{GDBN} will convert appropriate Scheme values to perform
958 @deffn {Scheme Procedure} value-add a b
961 @deffn {Scheme Procedure} value-sub a b
964 @deffn {Scheme Procedure} value-mul a b
967 @deffn {Scheme Procedure} value-div a b
970 @deffn {Scheme Procedure} value-rem a b
973 @deffn {Scheme Procedure} value-mod a b
976 @deffn {Scheme Procedure} value-pow a b
979 @deffn {Scheme Procedure} value-not a
982 @deffn {Scheme Procedure} value-neg a
985 @deffn {Scheme Procedure} value-pos a
988 @deffn {Scheme Procedure} value-abs a
991 @deffn {Scheme Procedure} value-lsh a b
994 @deffn {Scheme Procedure} value-rsh a b
997 @deffn {Scheme Procedure} value-min a b
1000 @deffn {Scheme Procedure} value-max a b
1003 @deffn {Scheme Procedure} value-lognot a
1006 @deffn {Scheme Procedure} value-logand a b
1009 @deffn {Scheme Procedure} value-logior a b
1012 @deffn {Scheme Procedure} value-logxor a b
1015 @deffn {Scheme Procedure} value=? a b
1018 @deffn {Scheme Procedure} value<? a b
1021 @deffn {Scheme Procedure} value<=? a b
1024 @deffn {Scheme Procedure} value>? a b
1027 @deffn {Scheme Procedure} value>=? a b
1030 Scheme does not provide a @code{not-equal} function,
1031 and thus Guile support in @value{GDBN} does not either.
1033 @node Types In Guile
1034 @subsubsection Types In Guile
1035 @cindex types in guile
1036 @cindex guile, working with types
1039 @value{GDBN} represents types from the inferior in objects of type
1042 The following type-related procedures are provided by the
1043 @code{(gdb)} module.
1045 @deffn {Scheme Procedure} type? object
1046 Return @code{#t} if @var{object} is an object of type @code{<gdb:type>}.
1047 Otherwise return @code{#f}.
1050 @deffn {Scheme Procedure} lookup-type name @r{[}#:block block@r{]}
1051 This function looks up a type by its @var{name}, which must be a string.
1053 If @var{block} is given, it is an object of type @code{<gdb:block>},
1054 and @var{name} is looked up in that scope.
1055 Otherwise, it is searched for globally.
1057 Ordinarily, this function will return an instance of @code{<gdb:type>}.
1058 If the named type cannot be found, it will throw an exception.
1061 @deffn {Scheme Procedure} type-code type
1062 Return the type code of @var{type}. The type code will be one of the
1063 @code{TYPE_CODE_} constants defined below.
1066 @deffn {Scheme Procedure} type-tag type
1067 Return the tag name of @var{type}. The tag name is the name after
1068 @code{struct}, @code{union}, or @code{enum} in C and C@t{++}; not all
1069 languages have this concept. If this type has no tag name, then
1070 @code{#f} is returned.
1073 @deffn {Scheme Procedure} type-name type
1074 Return the name of @var{type}.
1075 If this type has no name, then @code{#f} is returned.
1078 @deffn {Scheme Procedure} type-print-name type
1079 Return the print name of @var{type}.
1080 This returns something even for anonymous types.
1081 For example, for an anonymous C struct @code{"struct @{...@}"} is returned.
1084 @deffn {Scheme Procedure} type-sizeof type
1085 Return the size of this type, in target @code{char} units. Usually, a
1086 target's @code{char} type will be an 8-bit byte. However, on some
1087 unusual platforms, this type may have a different size.
1090 @deffn {Scheme Procedure} type-strip-typedefs type
1091 Return a new @code{<gdb:type>} that represents the real type of @var{type},
1092 after removing all layers of typedefs.
1095 @deffn {Scheme Procedure} type-array type n1 @r{[}n2@r{]}
1096 Return a new @code{<gdb:type>} object which represents an array of this
1097 type. If one argument is given, it is the inclusive upper bound of
1098 the array; in this case the lower bound is zero. If two arguments are
1099 given, the first argument is the lower bound of the array, and the
1100 second argument is the upper bound of the array. An array's length
1101 must not be negative, but the bounds can be.
1104 @deffn {Scheme Procedure} type-vector type n1 @r{[}n2@r{]}
1105 Return a new @code{<gdb:type>} object which represents a vector of this
1106 type. If one argument is given, it is the inclusive upper bound of
1107 the vector; in this case the lower bound is zero. If two arguments are
1108 given, the first argument is the lower bound of the vector, and the
1109 second argument is the upper bound of the vector. A vector's length
1110 must not be negative, but the bounds can be.
1112 The difference between an @code{array} and a @code{vector} is that
1113 arrays behave like in C: when used in expressions they decay to a pointer
1114 to the first element whereas vectors are treated as first class values.
1117 @deffn {Scheme Procedure} type-pointer type
1118 Return a new @code{<gdb:type>} object which represents a pointer to
1122 @deffn {Scheme Procedure} type-range type
1123 Return a list of two elements: the low bound and high bound of @var{type}.
1124 If @var{type} does not have a range, an exception is thrown.
1127 @deffn {Scheme Procedure} type-reference type
1128 Return a new @code{<gdb:type>} object which represents a reference to
1132 @deffn {Scheme Procedure} type-target type
1133 Return a new @code{<gdb:type>} object which represents the target type
1136 For a pointer type, the target type is the type of the pointed-to
1137 object. For an array type (meaning C-like arrays), the target type is
1138 the type of the elements of the array. For a function or method type,
1139 the target type is the type of the return value. For a complex type,
1140 the target type is the type of the elements. For a typedef, the
1141 target type is the aliased type.
1143 If the type does not have a target, this method will throw an
1147 @deffn {Scheme Procedure} type-const type
1148 Return a new @code{<gdb:type>} object which represents a
1149 @code{const}-qualified variant of @var{type}.
1152 @deffn {Scheme Procedure} type-volatile type
1153 Return a new @code{<gdb:type>} object which represents a
1154 @code{volatile}-qualified variant of @var{type}.
1157 @deffn {Scheme Procedure} type-unqualified type
1158 Return a new @code{<gdb:type>} object which represents an unqualified
1159 variant of @var{type}. That is, the result is neither @code{const} nor
1163 @deffn {Scheme Procedure} type-num-fields
1164 Return the number of fields of @code{<gdb:type>} @var{type}.
1167 @deffn {Scheme Procedure} type-fields type
1168 Return the fields of @var{type} as a list.
1169 For structure and union types, @code{fields} has the usual meaning.
1170 Range types have two fields, the minimum and maximum values. Enum types
1171 have one field per enum constant. Function and method types have one
1172 field per parameter. The base types of C@t{++} classes are also
1173 represented as fields. If the type has no fields, or does not fit
1174 into one of these categories, an empty list will be returned.
1175 @xref{Fields of a type in Guile}.
1178 @deffn {Scheme Procedure} make-field-iterator type
1179 Return the fields of @var{type} as a <gdb:iterator> object.
1180 @xref{Iterators In Guile}.
1183 @deffn {Scheme Procedure} type-field type field-name
1184 Return field named @var{field-name} in @var{type}.
1185 The result is an object of type @code{<gdb:field>}.
1186 @xref{Fields of a type in Guile}.
1187 If the type does not have fields, or @var{field-name} is not a field
1188 of @var{type}, an exception is thrown.
1190 For example, if @code{some-type} is a @code{<gdb:type>} instance holding
1191 a structure type, you can access its @code{foo} field with:
1194 (define bar (type-field some-type "foo"))
1197 @code{bar} will be a @code{<gdb:field>} object.
1200 @deffn {Scheme Procedure} type-has-field? type name
1201 Return @code{#t} if @code{<gdb:type>} @var{type} has field named @var{name}.
1202 Otherwise return @code{#f}.
1205 Each type has a code, which indicates what category this type falls
1206 into. The available type categories are represented by constants
1207 defined in the @code{(gdb)} module:
1211 The type is a pointer.
1213 @item TYPE_CODE_ARRAY
1214 The type is an array.
1216 @item TYPE_CODE_STRUCT
1217 The type is a structure.
1219 @item TYPE_CODE_UNION
1220 The type is a union.
1222 @item TYPE_CODE_ENUM
1223 The type is an enum.
1225 @item TYPE_CODE_FLAGS
1226 A bit flags type, used for things such as status registers.
1228 @item TYPE_CODE_FUNC
1229 The type is a function.
1232 The type is an integer type.
1235 A floating point type.
1237 @item TYPE_CODE_VOID
1238 The special type @code{void}.
1243 @item TYPE_CODE_RANGE
1244 A range type, that is, an integer type with bounds.
1246 @item TYPE_CODE_STRING
1247 A string type. Note that this is only used for certain languages with
1248 language-defined string types; C strings are not represented this way.
1250 @item TYPE_CODE_BITSTRING
1251 A string of bits. It is deprecated.
1253 @item TYPE_CODE_ERROR
1254 An unknown or erroneous type.
1256 @item TYPE_CODE_METHOD
1257 A method type, as found in C@t{++} or Java.
1259 @item TYPE_CODE_METHODPTR
1260 A pointer-to-member-function.
1262 @item TYPE_CODE_MEMBERPTR
1263 A pointer-to-member.
1268 @item TYPE_CODE_CHAR
1271 @item TYPE_CODE_BOOL
1274 @item TYPE_CODE_COMPLEX
1275 A complex float type.
1277 @item TYPE_CODE_TYPEDEF
1278 A typedef to some other type.
1280 @item TYPE_CODE_NAMESPACE
1281 A C@t{++} namespace.
1283 @item TYPE_CODE_DECFLOAT
1284 A decimal floating point type.
1286 @item TYPE_CODE_INTERNAL_FUNCTION
1287 A function internal to @value{GDBN}. This is the type used to represent
1288 convenience functions (@pxref{Convenience Funs}).
1291 Further support for types is provided in the @code{(gdb types)}
1292 Guile module (@pxref{Guile Types Module}).
1294 @anchor{Fields of a type in Guile}
1295 Each field is represented as an object of type @code{<gdb:field>}.
1297 The following field-related procedures are provided by the
1298 @code{(gdb)} module:
1300 @deffn {Scheme Procedure} field? object
1301 Return @code{#t} if @var{object} is an object of type @code{<gdb:field>}.
1302 Otherwise return @code{#f}.
1305 @deffn {Scheme Procedure} field-name field
1306 Return the name of the field, or @code{#f} for anonymous fields.
1309 @deffn {Scheme Procedure} field-type field
1310 Return the type of the field. This is usually an instance of
1311 @code{<gdb:type>}, but it can be @code{#f} in some situations.
1314 @deffn {Scheme Procedure} field-enumval field
1315 Return the enum value represented by @code{<gdb:field>} @var{field}.
1318 @deffn {Scheme Procedure} field-bitpos field
1319 Return the bit position of @code{<gdb:field>} @var{field}.
1320 This attribute is not available for @code{static} fields (as in
1324 @deffn {Scheme Procedure} field-bitsize field
1325 If the field is packed, or is a bitfield, return the size of
1326 @code{<gdb:field>} @var{field} in bits. Otherwise, zero is returned;
1327 in which case the field's size is given by its type.
1330 @deffn {Scheme Procedure} field-artificial? field
1331 Return @code{#t} if the field is artificial, usually meaning that
1332 it was provided by the compiler and not the user.
1333 Otherwise return @code{#f}.
1336 @deffn {Scheme Procedure} field-base-class? field
1337 Return @code{#t} if the field represents a base class of a C@t{++}
1339 Otherwise return @code{#f}.
1342 @node Guile Pretty Printing API
1343 @subsubsection Guile Pretty Printing API
1344 @cindex guile pretty printing api
1346 An example output is provided (@pxref{Pretty Printing}).
1348 A pretty-printer is represented by an object of type <gdb:pretty-printer>.
1349 Pretty-printer objects are created with @code{make-pretty-printer}.
1351 The following pretty-printer-related procedures are provided by the
1352 @code{(gdb)} module:
1354 @deffn {Scheme Procedure} make-pretty-printer name lookup-function
1355 Return a @code{<gdb:pretty-printer>} object named @var{name}.
1357 @var{lookup-function} is a function of one parameter: the value to
1358 be printed. If the value is handled by this pretty-printer, then
1359 @var{lookup-function} returns an object of type
1360 <gdb:pretty-printer-worker> to perform the actual pretty-printing.
1361 Otherwise @var{lookup-function} returns @code{#f}.
1364 @deffn {Scheme Procedure} pretty-printer? object
1365 Return @code{#t} if @var{object} is a @code{<gdb:pretty-printer>} object.
1366 Otherwise return @code{#f}.
1369 @deffn {Scheme Procedure} pretty-printer-enabled? pretty-printer
1370 Return @code{#t} if @var{pretty-printer} is enabled.
1371 Otherwise return @code{#f}.
1374 @deffn {Scheme Procedure} set-pretty-printer-enabled! pretty-printer flag
1375 Set the enabled flag of @var{pretty-printer} to @var{flag}.
1376 The value returned in unspecified.
1379 @deffn {Scheme Procedure} make-pretty-printer-worker display-hint to-string children
1380 Return an object of type @code{<gdb:pretty-printer-worker>}.
1382 This function takes three parameters:
1386 @var{display-hint} provides a hint to @value{GDBN} or @value{GDBN}
1387 front end via MI to change the formatting of the value being printed.
1388 The value must be a string or @code{#f} (meaning there is no hint).
1389 Several values for @var{display-hint}
1390 are predefined by @value{GDBN}:
1394 Indicate that the object being printed is ``array-like''. The CLI
1395 uses this to respect parameters such as @code{set print elements} and
1396 @code{set print array}.
1399 Indicate that the object being printed is ``map-like'', and that the
1400 children of this value can be assumed to alternate between keys and
1404 Indicate that the object being printed is ``string-like''. If the
1405 printer's @code{to-string} function returns a Guile string of some
1406 kind, then @value{GDBN} will call its internal language-specific
1407 string-printing function to format the string. For the CLI this means
1408 adding quotation marks, possibly escaping some characters, respecting
1409 @code{set print elements}, and the like.
1413 @var{to-string} is either a function of one parameter, the
1414 @code{<gdb:pretty-printer-worker>} object, or @code{#f}.
1416 When printing from the CLI, if the @code{to-string} method exists,
1417 then @value{GDBN} will prepend its result to the values returned by
1418 @code{children}. Exactly how this formatting is done is dependent on
1419 the display hint, and may change as more hints are added. Also,
1420 depending on the print settings (@pxref{Print Settings}), the CLI may
1421 print just the result of @code{to-string} in a stack trace, omitting
1422 the result of @code{children}.
1424 If this method returns a string, it is printed verbatim.
1426 Otherwise, if this method returns an instance of @code{<gdb:value>},
1427 then @value{GDBN} prints this value. This may result in a call to
1428 another pretty-printer.
1430 If instead the method returns a Guile value which is convertible to a
1431 @code{<gdb:value>}, then @value{GDBN} performs the conversion and prints
1432 the resulting value. Again, this may result in a call to another
1433 pretty-printer. Guile scalars (integers, floats, and booleans) and
1434 strings are convertible to @code{<gdb:value>}; other types are not.
1436 Finally, if this method returns @code{#f} then no further operations
1437 are peformed in this method and nothing is printed.
1439 If the result is not one of these types, an exception is raised.
1441 @var{to-string} may also be @code{#f} in which case it is left to
1442 @var{children} to print the value.
1445 @var{children} is either a function of one parameter, the
1446 @code{<gdb:pretty-printer-worker>} object, or @code{#f}.
1448 @value{GDBN} will call this function on a pretty-printer to compute the
1449 children of the pretty-printer's value.
1451 This function must return a <gdb:iterator> object.
1452 Each item returned by the iterator must be a tuple holding
1453 two elements. The first element is the ``name'' of the child; the
1454 second element is the child's value. The value can be any Guile
1455 object which is convertible to a @value{GDBN} value.
1457 If @var{children} is @code{#f}, @value{GDBN} will act
1458 as though the value has no children.
1462 @value{GDBN} provides a function which can be used to look up the
1463 default pretty-printer for a @code{<gdb:value>}:
1465 @deffn {Scheme Procedure} default-visualizer value
1466 This function takes a @code{<gdb:value>} object as an argument. If a
1467 pretty-printer for this value exists, then it is returned. If no such
1468 printer exists, then this returns @code{#f}.
1471 @node Selecting Guile Pretty-Printers
1472 @subsubsection Selecting Guile Pretty-Printers
1473 @cindex selecting guile pretty-printers
1475 The Guile list @code{*pretty-printers*} contains a set of
1476 @code{<gdb:pretty-printer>} registered objects.
1477 Printers in this list are called @code{global}
1478 printers, they're available when debugging any inferior.
1479 In addition to this, each @code{<gdb:objfile>} object contains its
1480 own set of pretty-printers (@pxref{Objfiles In Guile}).
1482 Pretty-printer lookup is done by passing the value to be printed to the
1483 lookup function of each enabled object in turn.
1484 Lookup stops when a lookup function returns a non-@code{#f} value
1485 or when the list is exhausted.
1487 @value{GDBN} first checks the result of @code{objfile-pretty-printers}
1488 of each @code{<gdb:objfile>} in the current program space and iteratively
1489 calls each enabled lookup function in the list for that @code{<gdb:objfile>}
1490 until a non-@code{#f} object is returned.
1491 Lookup functions must return either a @code{<gdb:pretty-printer-worker>}
1492 object or @code{#f}. Otherwise an exception is thrown.
1493 If no pretty-printer is found in the objfile lists, @value{GDBN} then
1494 searches the global pretty-printer list, calling each enabled function
1495 until a non-@code{#f} object is returned.
1497 The order in which the objfiles are searched is not specified. For a
1498 given list, functions are always invoked from the head of the list,
1499 and iterated over sequentially until the end of the list, or a
1500 @code{<gdb:pretty-printer-worker>} object is returned.
1502 For various reasons a pretty-printer may not work.
1503 For example, the underlying data structure may have changed and
1504 the pretty-printer is out of date.
1506 The consequences of a broken pretty-printer are severe enough that
1507 @value{GDBN} provides support for enabling and disabling individual
1508 printers. For example, if @code{print frame-arguments} is on,
1509 a backtrace can become highly illegible if any argument is printed
1510 with a broken printer.
1512 Pretty-printers are enabled and disabled from Scheme by calling
1513 @code{set-pretty-printer-enabled!}.
1514 @xref{Guile Pretty Printing API}.
1516 @node Writing a Guile Pretty-Printer
1517 @subsubsection Writing a Guile Pretty-Printer
1518 @cindex writing a Guile pretty-printer
1520 A pretty-printer consists of two basic parts: a lookup function to determine
1521 if the type is supported, and the printer itself.
1523 Here is an example showing how a @code{std::string} printer might be
1524 written. @xref{Guile Pretty Printing API}, for details.
1527 (define (make-my-string-printer value)
1528 "Print a my::string string"
1529 (make-pretty-printer-worker
1532 (value-field value "_data"))
1536 And here is an example showing how a lookup function for the printer
1537 example above might be written.
1540 (define (str-lookup-function pretty-printer value)
1541 (let ((tag (type-tag (value-type value))))
1543 (string-prefix? "std::string<" tag)
1544 (make-my-string-printer value))))
1547 Then to register this printer in the global printer list:
1550 (append-pretty-printer!
1551 (make-pretty-printer "my-string" str-lookup-function))
1554 The example lookup function extracts the value's type, and attempts to
1555 match it to a type that it can pretty-print. If it is a type the
1556 printer can pretty-print, it will return a <gdb:pretty-printer-worker> object.
1557 If not, it returns @code{#f}.
1559 We recommend that you put your core pretty-printers into a Guile
1560 package. If your pretty-printers are for use with a library, we
1561 further recommend embedding a version number into the package name.
1562 This practice will enable @value{GDBN} to load multiple versions of
1563 your pretty-printers at the same time, because they will have
1566 You should write auto-loaded code (@pxref{Guile Auto-loading}) such that it
1567 can be evaluated multiple times without changing its meaning. An
1568 ideal auto-load file will consist solely of @code{import}s of your
1569 printer modules, followed by a call to a register pretty-printers with
1570 the current objfile.
1572 Taken as a whole, this approach will scale nicely to multiple
1573 inferiors, each potentially using a different library version.
1574 Embedding a version number in the Guile package name will ensure that
1575 @value{GDBN} is able to load both sets of printers simultaneously.
1576 Then, because the search for pretty-printers is done by objfile, and
1577 because your auto-loaded code took care to register your library's
1578 printers with a specific objfile, @value{GDBN} will find the correct
1579 printers for the specific version of the library used by each
1582 To continue the @code{my::string} example,
1583 this code might appear in @code{(my-project my-library v1)}:
1587 (define (register-printers objfile)
1588 (append-objfile-pretty-printer!
1589 (make-pretty-printer "my-string" str-lookup-function)))
1593 And then the corresponding contents of the auto-load file would be:
1596 (use-modules (gdb) (my-project my-library v1))
1597 (register-printers (current-objfile))
1600 The previous example illustrates a basic pretty-printer.
1601 There are a few things that can be improved on.
1602 The printer only handles one type, whereas a library typically has
1603 several types. One could install a lookup function for each desired type
1604 in the library, but one could also have a single lookup function recognize
1605 several types. The latter is the conventional way this is handled.
1606 If a pretty-printer can handle multiple data types, then its
1607 @dfn{subprinters} are the printers for the individual data types.
1609 The @code{(gdb printing)} module provides a formal way of solving this
1610 problem (@pxref{Guile Printing Module}).
1611 Here is another example that handles multiple types.
1613 These are the types we are going to pretty-print:
1616 struct foo @{ int a, b; @};
1617 struct bar @{ struct foo x, y; @};
1620 Here are the printers:
1623 (define (make-foo-printer value)
1624 "Print a foo object"
1625 (make-pretty-printer-worker
1628 (format #f "a=<~a> b=<~a>"
1629 (value-field value "a") (value-field value "a")))
1632 (define (make-bar-printer value)
1633 "Print a bar object"
1634 (make-pretty-printer-worker
1637 (format #f "x=<~a> y=<~a>"
1638 (value-field value "x") (value-field value "y")))
1642 This example doesn't need a lookup function, that is handled by the
1643 @code{(gdb printing)} module. Instead a function is provided to build up
1644 the object that handles the lookup.
1647 (use-modules (gdb printing))
1649 (define (build-pretty-printer)
1650 (let ((pp (make-pretty-printer-collection "my-library")))
1651 (pp-collection-add-tag-printer "foo" make-foo-printer)
1652 (pp-collection-add-tag-printer "bar" make-bar-printer)
1656 And here is the autoload support:
1659 (use-modules (gdb) (my-library))
1660 (append-objfile-pretty-printer! (current-objfile) (build-pretty-printer))
1663 Finally, when this printer is loaded into @value{GDBN}, here is the
1664 corresponding output of @samp{info pretty-printer}:
1667 (gdb) info pretty-printer
1674 @node Commands In Guile
1675 @subsubsection Commands In Guile
1677 @cindex commands in guile
1678 @cindex guile commands
1679 You can implement new @value{GDBN} CLI commands in Guile. A CLI
1680 command object is created with the @code{make-command} Guile function,
1681 and added to @value{GDBN} with the @code{register-command!} Guile function.
1682 This two-step approach is taken to separate out the side-effect of adding
1683 the command to @value{GDBN} from @code{make-command}.
1685 There is no support for multi-line commands, that is commands that
1686 consist of multiple lines and are terminated with @code{end}.
1688 @c TODO: line length
1689 @deffn {Scheme Procedure} (make-command name @r{[}#:invoke invoke{]} @r{[}#:command-class command-class@r{]} @r{[}#:completer-class completer{]} @r{[}#:prefix? prefix@r{]} @r{[}#:doc doc-string{]})
1691 The argument @var{name} is the name of the command. If @var{name} consists of
1692 multiple words, then the initial words are looked for as prefix
1693 commands. In this case, if one of the prefix commands does not exist,
1694 an exception is raised.
1696 The result is the @code{<gdb:command>} object representing the command.
1697 The command is not usable until it has been registered with @value{GDBN}
1698 with @code{register-command!}.
1700 The rest of the arguments are optional.
1702 The argument @var{invoke} is a procedure of three arguments: @var{self},
1703 @var{args} and @var{from-tty}. The argument @var{self} is the
1704 @code{<gdb:command>} object representing the command.
1705 The argument @var{args} is a string representing the arguments passed to
1706 the command, after leading and trailing whitespace has been stripped.
1707 The argument @var{from-tty} is a boolean flag and specifies whether the
1708 command should consider itself to have been originated from the user
1709 invoking it interactively. If this function throws an exception,
1710 it is turned into a @value{GDBN} @code{error} call.
1711 Otherwise, the return value is ignored.
1713 The argument @var{command-class} is one of the @samp{COMMAND_} constants
1714 defined below. This argument tells @value{GDBN} how to categorize the
1715 new command in the help system. The default is @code{COMMAND_NONE}.
1717 The argument @var{completer} is either @code{#f}, one of the @samp{COMPLETE_}
1718 constants defined below, or a procedure, also defined below.
1719 This argument tells @value{GDBN} how to perform completion
1720 for this command. If not provided or if the value is @code{#f},
1721 then no completion is performed on the command.
1723 The argument @var{prefix} is a boolean flag indicating whether the new
1724 command is a prefix command; sub-commands of this command may be
1727 The argument @var{doc-string} is help text for the new command.
1728 If no documentation string is provided, the default value ``This command is
1729 not documented.'' is used.
1732 @deffn {Scheme Procedure} register-command! command
1733 Add @var{command}, a @code{<gdb:command>} object, to @value{GDBN}'s
1735 It is an error to register a command more than once.
1736 The result is unspecified.
1739 @deffn {Scheme Procedure} command? object
1740 Return @code{#t} if @var{object} is a @code{<gdb:command>} object.
1741 Otherwise return @code{#f}.
1744 @cindex don't repeat Guile command
1745 @deffn {Scheme Procedure} dont-repeat
1746 By default, a @value{GDBN} command is repeated when the user enters a
1747 blank line at the command prompt. A command can suppress this
1748 behavior by invoking the @code{dont-repeat} function. This is similar
1749 to the user command @code{dont-repeat}, see @ref{Define, dont-repeat}.
1752 @deffn {Scheme Procedure} string->argv string
1753 Convert a string to a list of strings split up according to
1754 @value{GDBN}'s argv parsing rules.
1755 It is recommended to use this for consistency.
1756 Arguments are separated by spaces and may be quoted.
1760 scheme@@(guile-user)> (string->argv "1 2\\ \\\"3 '4 \"5' \"6 '7\"")
1761 $1 = ("1" "2 \"3" "4 \"5" "6 '7")
1765 @deffn {Scheme Procedure} throw-user-error message . args
1766 Throw a @code{gdb:user-error} exception.
1767 The argument @var{message} is the error message as a format string, like the
1768 @var{fmt} argument to the @code{format} Scheme function.
1769 @xref{Formatted Output,,, guile, GNU Guile Reference Manual}.
1770 The argument @var{args} is a list of the optional arguments of @var{message}.
1772 This is used when the command detects a user error of some kind,
1773 say a bad command argument.
1776 (gdb) guile (use-modules (gdb))
1778 (register-command! (make-command "test-user-error"
1779 #:command-class COMMAND_OBSCURE
1780 #:invoke (lambda (self arg from-tty)
1781 (throw-user-error "Bad argument ~a" arg))))
1783 (gdb) test-user-error ugh
1784 ERROR: Bad argument ugh
1788 @cindex completion of Guile commands
1789 @deffn completer self text word
1790 If the @var{completer} option to @code{make-command} is a procedure,
1791 it takes three arguments: @var{self} which is the @code{<gdb:command>}
1792 object, and @var{text} and @var{word} which are both strings.
1793 The argument @var{text} holds the complete command line up to the cursor's
1794 location. The argument @var{word} holds the last word of the command line;
1795 this is computed using a word-breaking heuristic.
1797 All forms of completion are handled by this function, that is,
1798 the @key{TAB} and @key{M-?} key bindings (@pxref{Completion}),
1799 and the @code{complete} command (@pxref{Help, complete}).
1801 This procedure can return several kinds of values:
1805 If the return value is a list, the contents of the list are used as the
1806 completions. It is up to @var{completer} to ensure that the
1807 contents actually do complete the word. An empty list is
1808 allowed, it means that there were no completions available. Only
1809 string elements of the list are used; other elements in the
1813 If the return value is a @code{<gdb:iterator>} object, it is iterated over to
1814 obtain the completions. It is up to @code{completer-procedure} to ensure
1815 that the results actually do complete the word. Only
1816 string elements of the result are used; other elements in the
1817 sequence are ignored.
1820 All other results are treated as though there were no available
1825 When a new command is registered, it will have been declared as a member of
1826 some general class of commands. This is used to classify top-level
1827 commands in the on-line help system; note that prefix commands are not
1828 listed under their own category but rather that of their top-level
1829 command. The available classifications are represented by constants
1830 defined in the @code{gdb} module:
1834 The command does not belong to any particular class. A command in
1835 this category will not be displayed in any of the help categories.
1836 This is the default.
1838 @item COMMAND_RUNNING
1839 The command is related to running the inferior. For example,
1840 @code{start}, @code{step}, and @code{continue} are in this category.
1841 Type @kbd{help running} at the @value{GDBN} prompt to see a list of
1842 commands in this category.
1845 The command is related to data or variables. For example,
1846 @code{call}, @code{find}, and @code{print} are in this category. Type
1847 @kbd{help data} at the @value{GDBN} prompt to see a list of commands
1851 The command has to do with manipulation of the stack. For example,
1852 @code{backtrace}, @code{frame}, and @code{return} are in this
1853 category. Type @kbd{help stack} at the @value{GDBN} prompt to see a
1854 list of commands in this category.
1857 This class is used for file-related commands. For example,
1858 @code{file}, @code{list} and @code{section} are in this category.
1859 Type @kbd{help files} at the @value{GDBN} prompt to see a list of
1860 commands in this category.
1862 @item COMMAND_SUPPORT
1863 This should be used for ``support facilities'', generally meaning
1864 things that are useful to the user when interacting with @value{GDBN},
1865 but not related to the state of the inferior. For example,
1866 @code{help}, @code{make}, and @code{shell} are in this category. Type
1867 @kbd{help support} at the @value{GDBN} prompt to see a list of
1868 commands in this category.
1870 @item COMMAND_STATUS
1871 The command is an @samp{info}-related command, that is, related to the
1872 state of @value{GDBN} itself. For example, @code{info}, @code{macro},
1873 and @code{show} are in this category. Type @kbd{help status} at the
1874 @value{GDBN} prompt to see a list of commands in this category.
1876 @item COMMAND_BREAKPOINTS
1877 The command has to do with breakpoints. For example, @code{break},
1878 @code{clear}, and @code{delete} are in this category. Type @kbd{help
1879 breakpoints} at the @value{GDBN} prompt to see a list of commands in
1882 @item COMMAND_TRACEPOINTS
1883 The command has to do with tracepoints. For example, @code{trace},
1884 @code{actions}, and @code{tfind} are in this category. Type
1885 @kbd{help tracepoints} at the @value{GDBN} prompt to see a list of
1886 commands in this category.
1889 The command is a general purpose command for the user, and typically
1890 does not fit in one of the other categories.
1891 Type @kbd{help user-defined} at the @value{GDBN} prompt to see
1892 a list of commands in this category, as well as the list of gdb macros
1893 (@pxref{Sequences}).
1895 @item COMMAND_OBSCURE
1896 The command is only used in unusual circumstances, or is not of
1897 general interest to users. For example, @code{checkpoint},
1898 @code{fork}, and @code{stop} are in this category. Type @kbd{help
1899 obscure} at the @value{GDBN} prompt to see a list of commands in this
1902 @item COMMAND_MAINTENANCE
1903 The command is only useful to @value{GDBN} maintainers. The
1904 @code{maintenance} and @code{flushregs} commands are in this category.
1905 Type @kbd{help internals} at the @value{GDBN} prompt to see a list of
1906 commands in this category.
1909 A new command can use a predefined completion function, either by
1910 specifying it via an argument at initialization, or by returning it
1911 from the @code{completer} procedure. These predefined completion
1912 constants are all defined in the @code{gdb} module:
1916 This constant means that no completion should be done.
1918 @item COMPLETE_FILENAME
1919 This constant means that filename completion should be performed.
1921 @item COMPLETE_LOCATION
1922 This constant means that location completion should be done.
1923 @xref{Specify Location}.
1925 @item COMPLETE_COMMAND
1926 This constant means that completion should examine @value{GDBN}
1929 @item COMPLETE_SYMBOL
1930 This constant means that completion should be done using symbol names
1933 @item COMPLETE_EXPRESSION
1934 This constant means that completion should be done on expressions.
1935 Often this means completing on symbol names, but some language
1936 parsers also have support for completing on field names.
1939 The following code snippet shows how a trivial CLI command can be
1940 implemented in Guile:
1944 (register-command! (make-command "hello-world"
1945 #:command-class COMMAND_USER
1946 #:doc "Greet the whole world."
1947 #:invoke (lambda (self args from-tty) (display "Hello, World!\n"))))
1953 @node Parameters In Guile
1954 @subsubsection Parameters In Guile
1956 @cindex parameters in guile
1957 @cindex guile parameters
1959 You can implement new @value{GDBN} @dfn{parameters} using Guile
1960 @footnote{Note that @value{GDBN} parameters must not be confused with
1961 Guile’s parameter objects (@pxref{Parameters,,, guile, GNU Guile
1962 Reference Manual}).}.
1964 There are many parameters that already exist and can be set in
1965 @value{GDBN}. Two examples are: @code{set follow-fork} and
1966 @code{set charset}. Setting these parameters influences certain
1967 behavior in @value{GDBN}. Similarly, you can define parameters that
1968 can be used to influence behavior in custom Guile scripts and commands.
1970 A new parameter is defined with the @code{make-parameter} Guile function,
1971 and added to @value{GDBN} with the @code{register-parameter!} Guile function.
1972 This two-step approach is taken to separate out the side-effect of adding
1973 the parameter to @value{GDBN} from @code{make-parameter}.
1975 Parameters are exposed to the user via the @code{set} and
1976 @code{show} commands. @xref{Help}.
1979 @deffn {Scheme Procedure} (make-parameter name @r{[}#:command-class command-class@r{]} @r{[}#:parameter-type parameter-type{]} @r{[}#:enum-list enum-list@r{]} @r{[}#:set-func set-func{]} @r{[}#:show-func show-func{]} @r{[}#:doc doc{]} @r{[}#:set-doc set-doc{]} @r{[}#:show-doc show-doc{]} @r{[}#:initial-value initial-value{]})
1981 The argument @var{name} is the name of the new parameter. If @var{name}
1982 consists of multiple words, then the initial words are looked for as prefix
1983 parameters. An example of this can be illustrated with the
1984 @code{set print} set of parameters. If @var{name} is
1985 @code{print foo}, then @code{print} will be searched as the prefix
1986 parameter. In this case the parameter can subsequently be accessed in
1987 @value{GDBN} as @code{set print foo}.
1988 If @var{name} consists of multiple words, and no prefix parameter group
1989 can be found, an exception is raised.
1991 The result is the @code{<gdb:parameter>} object representing the parameter.
1992 The parameter is not usable until it has been registered with @value{GDBN}
1993 with @code{register-parameter!}.
1995 The rest of the arguments are optional.
1997 The argument @var{command-class} should be one of the @samp{COMMAND_} constants
1998 (@pxref{Commands In Guile}). This argument tells @value{GDBN} how to
1999 categorize the new parameter in the help system.
2000 The default is @code{COMMAND_NONE}.
2002 The argument @var{parameter-type} should be one of the @samp{PARAM_} constants
2003 defined below. This argument tells @value{GDBN} the type of the new
2004 parameter; this information is used for input validation and
2005 completion. The default is @code{PARAM_BOOLEAN}.
2007 If @var{parameter-type} is @code{PARAM_ENUM}, then
2008 @var{enum-list} must be a list of strings. These strings
2009 represent the possible values for the parameter.
2011 If @var{parameter-type} is not @code{PARAM_ENUM}, then the presence
2012 of @var{enum-list} will cause an exception to be thrown.
2014 The argument @var{set-func} is a function of one argument: @var{self} which
2015 is the @code{<gdb:parameter>} object representing the parameter.
2016 @value{GDBN} will call this function when a @var{parameter}'s value has
2017 been changed via the @code{set} API (for example, @kbd{set foo off}).
2018 The value of the parameter has already been set to the new value.
2019 This function must return a string to be displayed to the user.
2020 @value{GDBN} will add a trailing newline if the string is non-empty.
2021 @value{GDBN} generally doesn't print anything when a parameter is set,
2022 thus typically this function should return @samp{""}.
2023 A non-empty string result should typically be used for displaying warnings
2026 The argument @var{show-func} is a function of two arguments: @var{self} which
2027 is the @code{<gdb:parameter>} object representing the parameter, and
2028 @var{svalue} which is the string representation of the current value.
2029 @value{GDBN} will call this function when a @var{parameter}'s
2030 @code{show} API has been invoked (for example, @kbd{show foo}).
2031 This function must return a string, and will be displayed to the user.
2032 @value{GDBN} will add a trailing newline.
2034 The argument @var{doc} is the help text for the new parameter.
2035 If there is no documentation string, a default value is used.
2037 The argument @var{set-doc} is the help text for this parameter's
2040 The argument @var{show-doc} is the help text for this parameter's
2041 @code{show} command.
2043 The argument @var{initial-value} specifies the initial value of the parameter.
2044 If it is a function, it takes one parameter, the @code{<gdb:parameter>}
2045 object and its result is used as the initial value of the parameter.
2046 The initial value must be valid for the parameter type,
2047 otherwise an exception is thrown.
2050 @deffn {Scheme Procedure} register-parameter! parameter
2051 Add @var{parameter}, a @code{<gdb:parameter>} object, to @value{GDBN}'s
2053 It is an error to register a parameter more than once.
2054 The result is unspecified.
2057 @deffn {Scheme Procedure} parameter? object
2058 Return @code{#t} if @var{object} is a @code{<gdb:parameter>} object.
2059 Otherwise return @code{#f}.
2062 @deffn {Scheme Procedure} parameter-value parameter
2063 Return the value of @var{parameter} which may either be
2064 a @code{<gdb:parameter>} object or a string naming the parameter.
2067 @deffn {Scheme Procedure} set-parameter-value! parameter new-value
2068 Assign @var{parameter} the value of @var{new-value}.
2069 The argument @var{parameter} must be an object of type @code{<gdb:parameter>}.
2070 @value{GDBN} does validation when assignments are made.
2073 When a new parameter is defined, its type must be specified. The
2074 available types are represented by constants defined in the @code{gdb}
2079 The value is a plain boolean. The Guile boolean values, @code{#t}
2080 and @code{#f} are the only valid values.
2082 @item PARAM_AUTO_BOOLEAN
2083 The value has three possible states: true, false, and @samp{auto}. In
2084 Guile, true and false are represented using boolean constants, and
2085 @samp{auto} is represented using @code{#:auto}.
2087 @item PARAM_UINTEGER
2088 The value is an unsigned integer. The value of 0 should be
2089 interpreted to mean ``unlimited''.
2091 @item PARAM_ZINTEGER
2092 The value is an integer.
2094 @item PARAM_ZUINTEGER
2095 The value is an unsigned integer.
2097 @item PARAM_ZUINTEGER_UNLIMITED
2098 The value is an integer in the range @samp{[0, INT_MAX]}.
2099 A value of @samp{-1} means ``unlimited'', and other negative
2100 numbers are not allowed.
2103 The value is a string. When the user modifies the string, any escape
2104 sequences, such as @samp{\t}, @samp{\f}, and octal escapes, are
2105 translated into corresponding characters and encoded into the current
2108 @item PARAM_STRING_NOESCAPE
2109 The value is a string. When the user modifies the string, escapes are
2110 passed through untranslated.
2112 @item PARAM_OPTIONAL_FILENAME
2113 The value is a either a filename (a string), or @code{#f}.
2115 @item PARAM_FILENAME
2116 The value is a filename. This is just like
2117 @code{PARAM_STRING_NOESCAPE}, but uses file names for completion.
2120 The value is a string, which must be one of a collection of string
2121 constants provided when the parameter is created.
2124 @node Progspaces In Guile
2125 @subsubsection Program Spaces In Guile
2127 @cindex progspaces in guile
2128 @tindex <gdb:progspace>
2129 A program space, or @dfn{progspace}, represents a symbolic view
2130 of an address space.
2131 It consists of all of the objfiles of the program.
2132 @xref{Objfiles In Guile}.
2133 @xref{Inferiors and Programs, program spaces}, for more details
2134 about program spaces.
2136 Each progspace is represented by an instance of the @code{<gdb:progspace>}
2137 smob. @xref{GDB Scheme Data Types}.
2139 The following progspace-related functions are available in the
2140 @code{(gdb)} module:
2142 @deffn {Scheme Procedure} progspace? object
2143 Return @code{#t} if @var{object} is a @code{<gdb:progspace>} object.
2144 Otherwise return @code{#f}.
2147 @deffn {Scheme Procedure} progspace-valid? progspace
2148 Return @code{#t} if @var{progspace} is valid, @code{#f} if not.
2149 A @code{<gdb:progspace>} object can become invalid
2150 if the program it refers to is not loaded in @value{GDBN} any longer.
2153 @deffn {Scheme Procedure} current-progspace
2154 This function returns the program space of the currently selected inferior.
2155 There is always a current progspace, this never returns @code{#f}.
2156 @xref{Inferiors and Programs}.
2159 @deffn {Scheme Procedure} progspaces
2160 Return a list of all the progspaces currently known to @value{GDBN}.
2163 @deffn {Scheme Procedure} progspace-filename progspace
2164 Return the absolute file name of @var{progspace} as a string.
2165 This is the name of the file passed as the argument to the @code{file}
2166 or @code{symbol-file} commands.
2167 If the program space does not have an associated file name,
2168 then @code{#f} is returned. This occurs, for example, when @value{GDBN}
2169 is started without a program to debug.
2171 A @code{gdb:invalid-object-error} exception is thrown if @var{progspace}
2175 @deffn {Scheme Procedure} progspace-objfiles progspace
2176 Return the list of objfiles of @var{progspace}.
2177 The order of objfiles in the result is arbitrary.
2178 Each element is an object of type @code{<gdb:objfile>}.
2179 @xref{Objfiles In Guile}.
2181 A @code{gdb:invalid-object-error} exception is thrown if @var{progspace}
2185 @deffn {Scheme Procedure} progspace-pretty-printers progspace
2186 Return the list of pretty-printers of @var{progspace}.
2187 Each element is an object of type @code{<gdb:pretty-printer>}.
2188 @xref{Guile Pretty Printing API}, for more information.
2191 @deffn {Scheme Procedure} set-progspace-pretty-printers! progspace printer-list
2192 Set the list of registered @code{<gdb:pretty-printer>} objects for
2193 @var{progspace} to @var{printer-list}.
2194 @xref{Guile Pretty Printing API}, for more information.
2197 @node Objfiles In Guile
2198 @subsubsection Objfiles In Guile
2200 @cindex objfiles in guile
2201 @tindex <gdb:objfile>
2202 @value{GDBN} loads symbols for an inferior from various
2203 symbol-containing files (@pxref{Files}). These include the primary
2204 executable file, any shared libraries used by the inferior, and any
2205 separate debug info files (@pxref{Separate Debug Files}).
2206 @value{GDBN} calls these symbol-containing files @dfn{objfiles}.
2208 Each objfile is represented as an object of type @code{<gdb:objfile>}.
2210 The following objfile-related procedures are provided by the
2211 @code{(gdb)} module:
2213 @deffn {Scheme Procedure} objfile? object
2214 Return @code{#t} if @var{object} is a @code{<gdb:objfile>} object.
2215 Otherwise return @code{#f}.
2218 @deffn {Scheme Procedure} objfile-valid? objfile
2219 Return @code{#t} if @var{objfile} is valid, @code{#f} if not.
2220 A @code{<gdb:objfile>} object can become invalid
2221 if the object file it refers to is not loaded in @value{GDBN} any
2222 longer. All other @code{<gdb:objfile>} procedures will throw an exception
2223 if it is invalid at the time the procedure is called.
2226 @deffn {Scheme Procedure} objfile-filename objfile
2227 Return the file name of @var{objfile} as a string.
2230 @deffn {Scheme Procedure} objfile-pretty-printers objfile
2231 Return the list of registered @code{<gdb:pretty-printer>} objects for
2232 @var{objfile}. @xref{Guile Pretty Printing API}, for more information.
2235 @deffn {Scheme Procedure} set-objfile-pretty-printers! objfile printer-list
2236 Set the list of registered @code{<gdb:pretty-printer>} objects for
2237 @var{objfile} to @var{printer-list}. The
2238 @var{printer-list} must be a list of @code{<gdb:pretty-printer>} objects.
2239 @xref{Guile Pretty Printing API}, for more information.
2242 @deffn {Scheme Procedure} current-objfile
2243 When auto-loading a Guile script (@pxref{Guile Auto-loading}), @value{GDBN}
2244 sets the ``current objfile'' to the corresponding objfile. This
2245 function returns the current objfile. If there is no current objfile,
2246 this function returns @code{#f}.
2249 @deffn {Scheme Procedure} objfiles
2250 Return a list of all the objfiles in the current program space.
2253 @node Frames In Guile
2254 @subsubsection Accessing inferior stack frames from Guile.
2256 @cindex frames in guile
2257 When the debugged program stops, @value{GDBN} is able to analyze its call
2258 stack (@pxref{Frames,,Stack frames}). The @code{<gdb:frame>} class
2259 represents a frame in the stack. A @code{<gdb:frame>} object is only valid
2260 while its corresponding frame exists in the inferior's stack. If you try
2261 to use an invalid frame object, @value{GDBN} will throw a
2262 @code{gdb:invalid-object} exception (@pxref{Guile Exception Handling}).
2264 Two @code{<gdb:frame>} objects can be compared for equality with the
2265 @code{equal?} function, like:
2268 (@value{GDBP}) guile (equal? (newest-frame) (selected-frame))
2272 The following frame-related procedures are provided by the
2273 @code{(gdb)} module:
2275 @deffn {Scheme Procedure} frame? object
2276 Return @code{#t} if @var{object} is a @code{<gdb:frame>} object.
2277 Otherwise return @code{#f}.
2280 @deffn {Scheme Procedure} frame-valid? frame
2281 Returns @code{#t} if @var{frame} is valid, @code{#f} if not.
2282 A frame object can become invalid if the frame it refers to doesn't
2283 exist anymore in the inferior. All @code{<gdb:frame>} procedures will throw
2284 an exception if the frame is invalid at the time the procedure is called.
2287 @deffn {Scheme Procedure} frame-name frame
2288 Return the function name of @var{frame}, or @code{#f} if it can't be
2292 @deffn {Scheme Procedure} frame-arch frame
2293 Return the @code{<gdb:architecture>} object corresponding to @var{frame}'s
2294 architecture. @xref{Architectures In Guile}.
2297 @deffn {Scheme Procedure} frame-type frame
2298 Return the type of @var{frame}. The value can be one of:
2302 An ordinary stack frame.
2305 A fake stack frame that was created by @value{GDBN} when performing an
2306 inferior function call.
2309 A frame representing an inlined function. The function was inlined
2310 into a @code{NORMAL_FRAME} that is older than this one.
2312 @item TAILCALL_FRAME
2313 A frame representing a tail call. @xref{Tail Call Frames}.
2315 @item SIGTRAMP_FRAME
2316 A signal trampoline frame. This is the frame created by the OS when
2317 it calls into a signal handler.
2320 A fake stack frame representing a cross-architecture call.
2322 @item SENTINEL_FRAME
2323 This is like @code{NORMAL_FRAME}, but it is only used for the
2328 @deffn {Scheme Procedure} frame-unwind-stop-reason frame
2329 Return an integer representing the reason why it's not possible to find
2330 more frames toward the outermost frame. Use
2331 @code{unwind-stop-reason-string} to convert the value returned by this
2332 function to a string. The value can be one of:
2335 @item FRAME_UNWIND_NO_REASON
2336 No particular reason (older frames should be available).
2338 @item FRAME_UNWIND_NULL_ID
2339 The previous frame's analyzer returns an invalid result.
2341 @item FRAME_UNWIND_OUTERMOST
2342 This frame is the outermost.
2344 @item FRAME_UNWIND_UNAVAILABLE
2345 Cannot unwind further, because that would require knowing the
2346 values of registers or memory that have not been collected.
2348 @item FRAME_UNWIND_INNER_ID
2349 This frame ID looks like it ought to belong to a NEXT frame,
2350 but we got it for a PREV frame. Normally, this is a sign of
2351 unwinder failure. It could also indicate stack corruption.
2353 @item FRAME_UNWIND_SAME_ID
2354 This frame has the same ID as the previous one. That means
2355 that unwinding further would almost certainly give us another
2356 frame with exactly the same ID, so break the chain. Normally,
2357 this is a sign of unwinder failure. It could also indicate
2360 @item FRAME_UNWIND_NO_SAVED_PC
2361 The frame unwinder did not find any saved PC, but we needed
2362 one to unwind further.
2364 @item FRAME_UNWIND_MEMORY_ERROR
2365 The frame unwinder caused an error while trying to access memory.
2367 @item FRAME_UNWIND_FIRST_ERROR
2368 Any stop reason greater or equal to this value indicates some kind
2369 of error. This special value facilitates writing code that tests
2370 for errors in unwinding in a way that will work correctly even if
2371 the list of the other values is modified in future @value{GDBN}
2372 versions. Using it, you could write:
2375 (define reason (frame-unwind-stop-readon (selected-frame)))
2376 (define reason-str (unwind-stop-reason-string reason))
2377 (if (>= reason FRAME_UNWIND_FIRST_ERROR)
2378 (format #t "An error occured: ~s\n" reason-str))
2383 @deffn {Scheme Procedure} frame-pc frame
2384 Return the frame's resume address.
2387 @deffn {Scheme Procedure} frame-block frame
2388 Return the frame's code block as a @code{<gdb:block>} object.
2389 @xref{Blocks In Guile}.
2392 @deffn {Scheme Procedure} frame-function frame
2393 Return the symbol for the function corresponding to this frame
2394 as a @code{<gdb:symbol>} object, or @code{#f} if there isn't one.
2395 @xref{Symbols In Guile}.
2398 @deffn {Scheme Procedure} frame-older frame
2399 Return the frame that called @var{frame}.
2402 @deffn {Scheme Procedure} frame-newer frame
2403 Return the frame called by @var{frame}.
2406 @deffn {Scheme Procedure} frame-sal frame
2407 Return the frame's @code{<gdb:sal>} (symtab and line) object.
2408 @xref{Symbol Tables In Guile}.
2411 @deffn {Scheme Procedure} frame-read-var frame variable @r{[}#:block block@r{]}
2412 Return the value of @var{variable} in @var{frame}. If the optional
2413 argument @var{block} is provided, search for the variable from that
2414 block; otherwise start at the frame's current block (which is
2415 determined by the frame's current program counter). The
2416 @var{variable} must be given as a string or a @code{<gdb:symbol>}
2417 object, and @var{block} must be a @code{<gdb:block>} object.
2420 @deffn {Scheme Procedure} frame-select frame
2421 Set @var{frame} to be the selected frame. @xref{Stack, ,Examining the
2425 @deffn {Scheme Procedure} selected-frame
2426 Return the selected frame object. @xref{Selection,,Selecting a Frame}.
2429 @deffn {Scheme Procedure} newest-frame
2430 Return the newest frame object for the selected thread.
2433 @deffn {Scheme Procedure} unwind-stop-reason-string reason
2434 Return a string explaining the reason why @value{GDBN} stopped unwinding
2435 frames, as expressed by the given @var{reason} code (an integer, see the
2436 @code{frame-unwind-stop-reason} procedure above in this section).
2439 @node Blocks In Guile
2440 @subsubsection Accessing blocks from Guile.
2442 @cindex blocks in guile
2445 In @value{GDBN}, symbols are stored in blocks. A block corresponds
2446 roughly to a scope in the source code. Blocks are organized
2447 hierarchically, and are represented individually in Guile as an object
2448 of type @code{<gdb:block>}. Blocks rely on debugging information being
2451 A frame has a block. Please see @ref{Frames In Guile}, for a more
2452 in-depth discussion of frames.
2454 The outermost block is known as the @dfn{global block}. The global
2455 block typically holds public global variables and functions.
2457 The block nested just inside the global block is the @dfn{static
2458 block}. The static block typically holds file-scoped variables and
2461 @value{GDBN} provides a method to get a block's superblock, but there
2462 is currently no way to examine the sub-blocks of a block, or to
2463 iterate over all the blocks in a symbol table (@pxref{Symbol Tables In
2466 Here is a short example that should help explain blocks:
2469 /* This is in the global block. */
2472 /* This is in the static block. */
2473 static int file_scope;
2475 /* 'function' is in the global block, and 'argument' is
2476 in a block nested inside of 'function'. */
2477 int function (int argument)
2479 /* 'local' is in a block inside 'function'. It may or may
2480 not be in the same block as 'argument'. */
2484 /* 'inner' is in a block whose superblock is the one holding
2488 /* If this call is expanded by the compiler, you may see
2489 a nested block here whose function is 'inline_function'
2490 and whose superblock is the one holding 'inner'. */
2496 The following block-related procedures are provided by the
2497 @code{(gdb)} module:
2499 @deffn {Scheme Procedure} block? object
2500 Return @code{#t} if @var{object} is a @code{<gdb:block>} object.
2501 Otherwise return @code{#f}.
2504 @deffn {Scheme Procedure} block-valid? block
2505 Returns @code{#t} if @code{<gdb:block>} @var{block} is valid,
2506 @code{#f} if not. A block object can become invalid if the block it
2507 refers to doesn't exist anymore in the inferior. All other
2508 @code{<gdb:block>} methods will throw an exception if it is invalid at
2509 the time the procedure is called. The block's validity is also checked
2510 during iteration over symbols of the block.
2513 @deffn {Scheme Procedure} block-start block
2514 Return the start address of @code{<gdb:block>} @var{block}.
2517 @deffn {Scheme Procedure} block-end block
2518 Return the end address of @code{<gdb:block>} @var{block}.
2521 @deffn {Scheme Procedure} block-function block
2522 Return the name of @code{<gdb:block>} @var{block} represented as a
2523 @code{<gdb:symbol>} object.
2524 If the block is not named, then @code{#f} is returned.
2526 For ordinary function blocks, the superblock is the static block.
2527 However, you should note that it is possible for a function block to
2528 have a superblock that is not the static block -- for instance this
2529 happens for an inlined function.
2532 @deffn {Scheme Procedure} block-superblock block
2533 Return the block containing @code{<gdb:block>} @var{block}.
2534 If the parent block does not exist, then @code{#f} is returned.
2537 @deffn {Scheme Procedure} block-global-block block
2538 Return the global block associated with @code{<gdb:block>} @var{block}.
2541 @deffn {Scheme Procedure} block-static-block block
2542 Return the static block associated with @code{<gdb:block>} @var{block}.
2545 @deffn {Scheme Procedure} block-global? block
2546 Return @code{#t} if @code{<gdb:block>} @var{block} is a global block.
2547 Otherwise return @code{#f}.
2550 @deffn {Scheme Procedure} block-static? block
2551 Return @code{#t} if @code{<gdb:block>} @var{block} is a static block.
2552 Otherwise return @code{#f}.
2555 @deffn {Scheme Procedure} block-symbols
2556 Return a list of all symbols (as <gdb:symbol> objects) in
2557 @code{<gdb:block>} @var{block}.
2560 @deffn {Scheme Procedure} make-block-symbols-iterator block
2561 Return an object of type @code{<gdb:iterator>} that will iterate
2562 over all symbols of the block.
2563 Guile programs should not assume that a specific block object will
2564 always contain a given symbol, since changes in @value{GDBN} features and
2565 infrastructure may cause symbols move across blocks in a symbol table.
2566 @xref{Iterators In Guile}.
2569 @deffn {Scheme Procedure} block-symbols-progress?
2570 Return #t if the object is a <gdb:block-symbols-progress> object.
2571 This object would be obtained from the @code{progress} element of the
2572 @code{<gdb:iterator>} object returned by @code{make-block-symbols-iterator}.
2575 @deffn {Scheme Procedure} lookup-block pc
2576 Return the innermost @code{<gdb:block>} containing the given @var{pc}
2577 value. If the block cannot be found for the @var{pc} value specified,
2578 the function will return @code{#f}.
2581 @node Symbols In Guile
2582 @subsubsection Guile representation of Symbols.
2584 @cindex symbols in guile
2585 @tindex <gdb:symbol>
2587 @value{GDBN} represents every variable, function and type as an
2588 entry in a symbol table. @xref{Symbols, ,Examining the Symbol Table}.
2589 Guile represents these symbols in @value{GDBN} with the
2590 @code{<gdb:symbol>} object.
2592 The following symbol-related procedures are provided by the
2593 @code{(gdb)} module:
2595 @deffn {Scheme Procedure} symbol? object
2596 Return @code{#t} if @var{object} is an object of type @code{<gdb:symbol>}.
2597 Otherwise return @code{#f}.
2600 @deffn {Scheme Procedure} symbol-valid? symbol
2601 Return @code{#t} if the @code{<gdb:symbol>} object is valid,
2602 @code{#f} if not. A @code{<gdb:symbol>} object can become invalid if
2603 the symbol it refers to does not exist in @value{GDBN} any longer.
2604 All other @code{<gdb:symbol>} procedures will throw an exception if it is
2605 invalid at the time the procedure is called.
2608 @deffn {Scheme Procedure} symbol-type symbol
2609 Return the type of @var{symbol} or @code{#f} if no type is recorded.
2610 The result is an object of type @code{<gdb:type>}.
2611 @xref{Types In Guile}.
2614 @deffn {Scheme Procedure} symbol-symtab symbol
2615 Return the symbol table in which @var{symbol} appears.
2616 The result is an object of type @code{<gdb:symtab>}.
2617 @xref{Symbol Tables In Guile}.
2620 @deffn {Scheme Procedure} symbol-line symbol
2621 Return the line number in the source code at which @var{symbol} was defined.
2625 @deffn {Scheme Procedure} symbol-name symbol
2626 Return the name of @var{symbol} as a string.
2629 @deffn {Scheme Procedure} symbol-linkage-name symbol
2630 Return the name of @var{symbol}, as used by the linker (i.e., may be mangled).
2633 @deffn {Scheme Procedure} symbol-print-name symbol
2634 Return the name of @var{symbol} in a form suitable for output. This is either
2635 @code{name} or @code{linkage_name}, depending on whether the user
2636 asked @value{GDBN} to display demangled or mangled names.
2639 @deffn {Scheme Procedure} symbol-addr-class symbol
2640 Return the address class of the symbol. This classifies how to find the value
2641 of a symbol. Each address class is a constant defined in the
2642 @code{(gdb)} module and described later in this chapter.
2645 @deffn {Scheme Procedure} symbol-needs-frame? symbol
2646 Return @code{#t} if evaluating @var{symbol}'s value requires a frame
2647 (@pxref{Frames In Guile}) and @code{#f} otherwise. Typically,
2648 local variables will require a frame, but other symbols will not.
2651 @deffn {Scheme Procedure} symbol-argument? symbol
2652 Return @code{#t} if @var{symbol} is an argument of a function.
2653 Otherwise return @code{#f}.
2656 @deffn {Scheme Procedure} symbol-constant? symbol
2657 Return @code{#t} if @var{symbol} is a constant.
2658 Otherwise return @code{#f}.
2661 @deffn {Scheme Procedure} symbol-function? symbol
2662 Return @code{#t} if @var{symbol} is a function or a method.
2663 Otherwise return @code{#f}.
2666 @deffn {Scheme Procedure} symbol-variable? symbol
2667 Return @code{#t} if @var{symbol} is a variable.
2668 Otherwise return @code{#f}.
2671 @deffn {Scheme Procedure} symbol-value symbol @r{[}#:frame frame@r{]}
2672 Compute the value of @var{symbol}, as a @code{<gdb:value>}. For
2673 functions, this computes the address of the function, cast to the
2674 appropriate type. If the symbol requires a frame in order to compute
2675 its value, then @var{frame} must be given. If @var{frame} is not
2676 given, or if @var{frame} is invalid, then an exception is thrown.
2679 @c TODO: line length
2680 @deffn {Scheme Procedure} lookup-symbol name @r{[}#:block block@r{]} @r{[}#:domain domain@r{]}
2681 This function searches for a symbol by name. The search scope can be
2682 restricted to the parameters defined in the optional domain and block
2685 @var{name} is the name of the symbol. It must be a string. The
2686 optional @var{block} argument restricts the search to symbols visible
2687 in that @var{block}. The @var{block} argument must be a
2688 @code{<gdb:block>} object. If omitted, the block for the current frame
2689 is used. The optional @var{domain} argument restricts
2690 the search to the domain type. The @var{domain} argument must be a
2691 domain constant defined in the @code{(gdb)} module and described later
2694 The result is a list of two elements.
2695 The first element is a @code{<gdb:symbol>} object or @code{#f} if the symbol
2697 If the symbol is found, the second element is @code{#t} if the symbol
2698 is a field of a method's object (e.g., @code{this} in C@t{++}),
2699 otherwise it is @code{#f}.
2700 If the symbol is not found, the second element is @code{#f}.
2703 @deffn {Scheme Procedure} lookup-global-symbol name @r{[}#:domain domain@r{]}
2704 This function searches for a global symbol by name.
2705 The search scope can be restricted by the domain argument.
2707 @var{name} is the name of the symbol. It must be a string.
2708 The optional @var{domain} argument restricts the search to the domain type.
2709 The @var{domain} argument must be a domain constant defined in the @code{(gdb)}
2710 module and described later in this chapter.
2712 The result is a @code{<gdb:symbol>} object or @code{#f} if the symbol
2716 The available domain categories in @code{<gdb:symbol>} are represented
2717 as constants in the @code{(gdb)} module:
2720 @item SYMBOL_UNDEF_DOMAIN
2721 This is used when a domain has not been discovered or none of the
2722 following domains apply. This usually indicates an error either
2723 in the symbol information or in @value{GDBN}'s handling of symbols.
2725 @item SYMBOL_VAR_DOMAIN
2726 This domain contains variables, function names, typedef names and enum
2729 @item SYMBOL_STRUCT_DOMAIN
2730 This domain holds struct, union and enum type names.
2732 @item SYMBOL_LABEL_DOMAIN
2733 This domain contains names of labels (for gotos).
2735 @item SYMBOL_VARIABLES_DOMAIN
2736 This domain holds a subset of the @code{SYMBOLS_VAR_DOMAIN}; it
2737 contains everything minus functions and types.
2739 @item SYMBOL_FUNCTION_DOMAIN
2740 This domain contains all functions.
2742 @item SYMBOL_TYPES_DOMAIN
2743 This domain contains all types.
2746 The available address class categories in @code{<gdb:symbol>} are represented
2747 as constants in the @code{gdb} module:
2750 @item SYMBOL_LOC_UNDEF
2751 If this is returned by address class, it indicates an error either in
2752 the symbol information or in @value{GDBN}'s handling of symbols.
2754 @item SYMBOL_LOC_CONST
2755 Value is constant int.
2757 @item SYMBOL_LOC_STATIC
2758 Value is at a fixed address.
2760 @item SYMBOL_LOC_REGISTER
2761 Value is in a register.
2763 @item SYMBOL_LOC_ARG
2764 Value is an argument. This value is at the offset stored within the
2765 symbol inside the frame's argument list.
2767 @item SYMBOL_LOC_REF_ARG
2768 Value address is stored in the frame's argument list. Just like
2769 @code{LOC_ARG} except that the value's address is stored at the
2770 offset, not the value itself.
2772 @item SYMBOL_LOC_REGPARM_ADDR
2773 Value is a specified register. Just like @code{LOC_REGISTER} except
2774 the register holds the address of the argument instead of the argument
2777 @item SYMBOL_LOC_LOCAL
2778 Value is a local variable.
2780 @item SYMBOL_LOC_TYPEDEF
2781 Value not used. Symbols in the domain @code{SYMBOL_STRUCT_DOMAIN} all
2784 @item SYMBOL_LOC_BLOCK
2787 @item SYMBOL_LOC_CONST_BYTES
2788 Value is a byte-sequence.
2790 @item SYMBOL_LOC_UNRESOLVED
2791 Value is at a fixed address, but the address of the variable has to be
2792 determined from the minimal symbol table whenever the variable is
2795 @item SYMBOL_LOC_OPTIMIZED_OUT
2796 The value does not actually exist in the program.
2798 @item SYMBOL_LOC_COMPUTED
2799 The value's address is a computed location.
2802 @node Symbol Tables In Guile
2803 @subsubsection Symbol table representation in Guile.
2805 @cindex symbol tables in guile
2806 @tindex <gdb:symtab>
2809 Access to symbol table data maintained by @value{GDBN} on the inferior
2810 is exposed to Guile via two objects: @code{<gdb:sal>} (symtab-and-line) and
2811 @code{<gdb:symtab>}. Symbol table and line data for a frame is returned
2812 from the @code{frame-find-sal} @code{<gdb:frame>} procedure.
2813 @xref{Frames In Guile}.
2815 For more information on @value{GDBN}'s symbol table management, see
2816 @ref{Symbols, ,Examining the Symbol Table}.
2818 The following symtab-related procedures are provided by the
2819 @code{(gdb)} module:
2821 @deffn {Scheme Procedure} symtab? object
2822 Return @code{#t} if @var{object} is an object of type @code{<gdb:symtab>}.
2823 Otherwise return @code{#f}.
2826 @deffn {Scheme Procedure} symtab-valid? symtab
2827 Return @code{#t} if the @code{<gdb:symtab>} object is valid,
2828 @code{#f} if not. A @code{<gdb:symtab>} object becomes invalid when
2829 the symbol table it refers to no longer exists in @value{GDBN}.
2830 All other @code{<gdb:symtab>} procedures will throw an exception
2831 if it is invalid at the time the procedure is called.
2834 @deffn {Scheme Procedure} symtab-filename symtab
2835 Return the symbol table's source filename.
2838 @deffn {Scheme Procedure} symtab-fullname symtab
2839 Return the symbol table's source absolute file name.
2842 @deffn {Scheme Procedure} symtab-objfile symtab
2843 Return the symbol table's backing object file. @xref{Objfiles In Guile}.
2846 @deffn {Scheme Procedure} symtab-global-block symtab
2847 Return the global block of the underlying symbol table.
2848 @xref{Blocks In Guile}.
2851 @deffn {Scheme Procedure} symtab-static-block symtab
2852 Return the static block of the underlying symbol table.
2853 @xref{Blocks In Guile}.
2856 The following symtab-and-line-related procedures are provided by the
2857 @code{(gdb)} module:
2859 @deffn {Scheme Procedure} sal? object
2860 Return @code{#t} if @var{object} is an object of type @code{<gdb:sal>}.
2861 Otherwise return @code{#f}.
2864 @deffn {Scheme Procedure} sal-valid? sal
2865 Return @code{#t} if @var{sal} is valid, @code{#f} if not.
2866 A @code{<gdb:sal>} object becomes invalid when the Symbol table object
2867 it refers to no longer exists in @value{GDBN}. All other
2868 @code{<gdb:sal>} procedures will throw an exception if it is
2869 invalid at the time the procedure is called.
2872 @deffn {Scheme Procedure} sal-symtab sal
2873 Return the symbol table object (@code{<gdb:symtab>}) for @var{sal}.
2876 @deffn {Scheme Procedure} sal-line sal
2877 Return the line number for @var{sal}.
2880 @deffn {Scheme Procedure} sal-pc sal
2881 Return the start of the address range occupied by code for @var{sal}.
2884 @deffn {Scheme Procedure} sal-last sal
2885 Return the end of the address range occupied by code for @var{sal}.
2888 @deffn {Scheme Procedure} find-pc-line pc
2889 Return the @code{<gdb:sal>} object corresponding to the @var{pc} value.
2890 If an invalid value of @var{pc} is passed as an argument, then the
2891 @code{symtab} and @code{line} attributes of the returned @code{<gdb:sal>}
2892 object will be @code{#f} and 0 respectively.
2895 @node Breakpoints In Guile
2896 @subsubsection Manipulating breakpoints using Guile
2898 @cindex breakpoints in guile
2899 @tindex <gdb:breakpoint>
2901 Breakpoints in Guile are represented by objects of type
2902 @code{<gdb:breakpoint>}. New breakpoints can be created with the
2903 @code{make-breakpoint} Guile function, and then added to @value{GDBN} with the
2904 @code{register-breakpoint!} Guile function.
2905 This two-step approach is taken to separate out the side-effect of adding
2906 the breakpoint to @value{GDBN} from @code{make-breakpoint}.
2908 Support is also provided to view and manipulate breakpoints created
2911 The following breakpoint-related procedures are provided by the
2912 @code{(gdb)} module:
2914 @c TODO: line length
2915 @deffn {Scheme Procedure} make-breakpoint location @r{[}#:type type@r{]} @r{[}#:wp-class wp-class@r{]} @r{[}#:internal internal@r{]}
2916 Create a new breakpoint at @var{location}, a string naming the
2917 location of the breakpoint, or an expression that defines a watchpoint.
2918 The contents can be any location recognized by the @code{break} command,
2919 or in the case of a watchpoint, by the @code{watch} command.
2921 The breakpoint is initially marked as @samp{invalid}.
2922 The breakpoint is not usable until it has been registered with @value{GDBN}
2923 with @code{register-breakpoint!}, at which point it becomes @samp{valid}.
2924 The result is the @code{<gdb:breakpoint>} object representing the breakpoint.
2926 The optional @var{type} denotes the breakpoint to create.
2927 This argument can be either @code{BP_BREAKPOINT} or @code{BP_WATCHPOINT},
2928 and defaults to @code{BP_BREAKPOINT}.
2930 The optional @var{wp-class} argument defines the class of watchpoint to
2931 create, if @var{type} is @code{BP_WATCHPOINT}. If a watchpoint class is
2932 not provided, it is assumed to be a @code{WP_WRITE} class.
2934 The optional @var{internal} argument allows the breakpoint to become
2935 invisible to the user. The breakpoint will neither be reported when
2936 registered, nor will it be listed in the output from @code{info breakpoints}
2937 (but will be listed with the @code{maint info breakpoints} command).
2938 If an internal flag is not provided, the breakpoint is visible
2941 When a watchpoint is created, @value{GDBN} will try to create a
2942 hardware assisted watchpoint. If successful, the type of the watchpoint
2943 is changed from @code{BP_WATCHPOINT} to @code{BP_HARDWARE_WATCHPOINT}
2944 for @code{WP_WRITE}, @code{BP_READ_WATCHPOINT} for @code{WP_READ},
2945 and @code{BP_ACCESS_WATCHPOINT} for @code{WP_ACCESS}.
2946 If not successful, the type of the watchpoint is left as @code{WP_WATCHPOINT}.
2948 The available types are represented by constants defined in the @code{gdb}
2953 Normal code breakpoint.
2956 Watchpoint breakpoint.
2958 @item BP_HARDWARE_WATCHPOINT
2959 Hardware assisted watchpoint.
2960 This value cannot be specified when creating the breakpoint.
2962 @item BP_READ_WATCHPOINT
2963 Hardware assisted read watchpoint.
2964 This value cannot be specified when creating the breakpoint.
2966 @item BP_ACCESS_WATCHPOINT
2967 Hardware assisted access watchpoint.
2968 This value cannot be specified when creating the breakpoint.
2971 The available watchpoint types represented by constants are defined in the
2972 @code{(gdb)} module:
2976 Read only watchpoint.
2979 Write only watchpoint.
2982 Read/Write watchpoint.
2987 @deffn {Scheme Procedure} register-breakpoint! breakpoint
2988 Add @var{breakpoint}, a @code{<gdb:breakpoint>} object, to @value{GDBN}'s
2989 list of breakpoints. The breakpoint must have been created with
2990 @code{make-breakpoint}. One cannot register breakpoints that have been
2991 created outside of Guile. Once a breakpoint is registered it becomes
2993 It is an error to register an already registered breakpoint.
2994 The result is unspecified.
2997 @deffn {Scheme Procedure} delete-breakpoint! breakpoint
2998 Remove @var{breakpoint} from @value{GDBN}'s list of breakpoints.
2999 This also invalidates the Guile @var{breakpoint} object.
3000 Any further attempt to access the object will throw an exception.
3002 If @var{breakpoint} was created from Guile with @code{make-breakpoint}
3003 it may be re-registered with @value{GDBN}, in which case the breakpoint
3004 becomes valid again.
3007 @deffn {Scheme Procedure} breakpoints
3008 Return a list of all breakpoints.
3009 Each element of the list is a @code{<gdb:breakpoint>} object.
3012 @deffn {Scheme Procedure} breakpoint? object
3013 Return @code{#t} if @var{object} is a @code{<gdb:breakpoint>} object,
3014 and @code{#f} otherwise.
3017 @deffn {Scheme Procedure} breakpoint-valid? breakpoint
3018 Return @code{#t} if @var{breakpoint} is valid, @code{#f} otherwise.
3019 Breakpoints created with @code{make-breakpoint} are marked as invalid
3020 until they are registered with @value{GDBN} with @code{register-breakpoint!}.
3021 A @code{<gdb:breakpoint>} object can become invalid
3022 if the user deletes the breakpoint. In this case, the object still
3023 exists, but the underlying breakpoint does not. In the cases of
3024 watchpoint scope, the watchpoint remains valid even if execution of the
3025 inferior leaves the scope of that watchpoint.
3028 @deffn {Scheme Procedure} breakpoint-number breakpoint
3029 Return the breakpoint's number --- the identifier used by
3030 the user to manipulate the breakpoint.
3033 @deffn {Scheme Procedure} breakpoint-type breakpoint
3034 Return the breakpoint's type --- the identifier used to
3035 determine the actual breakpoint type or use-case.
3038 @deffn {Scheme Procedure} breakpoint-visible? breakpoint
3039 Return @code{#t} if the breakpoint is visible to the user
3040 when hit, or when the @samp{info breakpoints} command is run.
3041 Otherwise return @code{#f}.
3044 @deffn {Scheme Procedure} breakpoint-location breakpoint
3045 Return the location of the breakpoint, as specified by
3046 the user. It is a string. If the breakpoint does not have a location
3047 (that is, it is a watchpoint) return @code{#f}.
3050 @deffn {Scheme Procedure} breakpoint-expression breakpoint
3051 Return the breakpoint expression, as specified by the user. It is a string.
3052 If the breakpoint does not have an expression (the breakpoint is not a
3053 watchpoint) return @code{#f}.
3056 @deffn {Scheme Procedure} breakpoint-enabled? breakpoint
3057 Return @code{#t} if the breakpoint is enabled, and @code{#f} otherwise.
3060 @deffn {Scheme Procedure} set-breakpoint-enabled! breakpoint flag
3061 Set the enabled state of @var{breakpoint} to @var{flag}.
3062 If flag is @code{#f} it is disabled, otherwise it is enabled.
3065 @deffn {Scheme Procedure} breakpoint-silent? breakpoint
3066 Return @code{#t} if the breakpoint is silent, and @code{#f} otherwise.
3068 Note that a breakpoint can also be silent if it has commands and the
3069 first command is @code{silent}. This is not reported by the
3070 @code{silent} attribute.
3073 @deffn {Scheme Procedure} set-breakpoint-silent! breakpoint flag
3074 Set the silent state of @var{breakpoint} to @var{flag}.
3075 If flag is @code{#f} the breakpoint is made silent,
3076 otherwise it is made non-silent (or noisy).
3079 @deffn {Scheme Procedure} breakpoint-ignore-count breakpoint
3080 Return the ignore count for @var{breakpoint}.
3083 @deffn {Scheme Procedure} set-breakpoint-ignore-count! breakpoint count
3084 Set the ignore count for @var{breakpoint} to @var{count}.
3087 @deffn {Scheme Procedure} breakpoint-hit-count breakpoint
3088 Return hit count of @var{breakpoint}.
3091 @deffn {Scheme Procedure} set-breakpoint-hit-count! breakpoint count
3092 Set the hit count of @var{breakpoint} to @var{count}.
3093 At present, @var{count} must be zero.
3096 @deffn {Scheme Procedure} breakpoint-thread breakpoint
3097 Return the thread-id for thread-specific breakpoint @var{breakpoint}.
3098 Return #f if @var{breakpoint} is not thread-specific.
3101 @deffn {Scheme Procedure} set-breakpoint-thread! breakpoint thread-id|#f
3102 Set the thread-id for @var{breakpoint} to @var{thread-id}.
3103 If set to @code{#f}, the breakpoint is no longer thread-specific.
3106 @deffn {Scheme Procedure} breakpoint-task breakpoint
3107 If the breakpoint is Ada task-specific, return the Ada task id.
3108 If the breakpoint is not task-specific (or the underlying
3109 language is not Ada), return @code{#f}.
3112 @deffn {Scheme Procedure} set-breakpoint-task! breakpoint task
3113 Set the Ada task of @var{breakpoint} to @var{task}.
3114 If set to @code{#f}, the breakpoint is no longer task-specific.
3117 @deffn {Scheme Procedure} breakpoint-condition breakpoint
3118 Return the condition of @var{breakpoint}, as specified by the user.
3119 It is a string. If there is no condition, return @code{#f}.
3122 @deffn {Scheme Procedure} set-breakpoint-condition! breakpoint condition
3123 Set the condition of @var{breakpoint} to @var{condition},
3124 which must be a string. If set to @code{#f} then the breakpoint
3125 becomes unconditional.
3128 @deffn {Scheme Procedure} breakpoint-stop breakpoint
3129 Return the stop predicate of @var{breakpoint}.
3130 See @code{set-breakpoint-stop!} below in this section.
3133 @deffn {Scheme Procedure} set-breakpoint-stop! breakpoint procedure|#f
3134 Set the stop predicate of @var{breakpoint}. The predicate
3135 @var{procedure} takes one argument: the <gdb:breakpoint> object.
3136 If this predicate is set to a procedure then it is invoked whenever
3137 the inferior reaches this breakpoint. If it returns @code{#t},
3138 or any non-@code{#f} value, then the inferior is stopped,
3139 otherwise the inferior will continue.
3141 If there are multiple breakpoints at the same location with a
3142 @code{stop} predicate, each one will be called regardless of the
3143 return status of the previous. This ensures that all @code{stop}
3144 predicates have a chance to execute at that location. In this scenario
3145 if one of the methods returns @code{#t} but the others return
3146 @code{#f}, the inferior will still be stopped.
3148 You should not alter the execution state of the inferior (i.e.@:, step,
3149 next, etc.), alter the current frame context (i.e.@:, change the current
3150 active frame), or alter, add or delete any breakpoint. As a general
3151 rule, you should not alter any data within @value{GDBN} or the inferior
3154 Example @code{stop} implementation:
3157 (define (my-stop? bkpt)
3158 (let ((int-val (parse-and-eval "foo")))
3159 (value=? int-val 3)))
3160 (define bkpt (make-breakpoint "main.c:42"))
3161 (register-breakpoint! bkpt)
3162 (set-breakpoint-stop! bkpt my-stop?)
3166 @deffn {Scheme Procedure} breakpoint-commands breakpoint
3167 Return the commands attached to @var{breakpoint} as a string,
3168 or @code{#f} if there are none.
3171 @node Lazy Strings In Guile
3172 @subsubsection Guile representation of lazy strings.
3174 @cindex lazy strings in guile
3175 @tindex <gdb:lazy-string>
3177 A @dfn{lazy string} is a string whose contents is not retrieved or
3178 encoded until it is needed.
3180 A @code{<gdb:lazy-string>} is represented in @value{GDBN} as an
3181 @code{address} that points to a region of memory, an @code{encoding}
3182 that will be used to encode that region of memory, and a @code{length}
3183 to delimit the region of memory that represents the string. The
3184 difference between a @code{<gdb:lazy-string>} and a string wrapped within
3185 a @code{<gdb:value>} is that a @code{<gdb:lazy-string>} will be treated
3186 differently by @value{GDBN} when printing. A @code{<gdb:lazy-string>} is
3187 retrieved and encoded during printing, while a @code{<gdb:value>}
3188 wrapping a string is immediately retrieved and encoded on creation.
3190 The following lazy-string-related procedures are provided by the
3191 @code{(gdb)} module:
3193 @deffn {Scheme Procedure} lazy-string? object
3194 Return @code{#t} if @var{object} is an object of type @code{<gdb:lazy-string>}.
3195 Otherwise return @code{#f}.
3198 @deffn {Scheme Procedure} lazy-string-address lazy-sring
3199 Return the address of @var{lazy-string}.
3202 @deffn {Scheme Procedure} lazy-string-length lazy-string
3203 Return the length of @var{lazy-string} in characters. If the
3204 length is -1, then the string will be fetched and encoded up to the
3205 first null of appropriate width.
3208 @deffn {Scheme Procedure} lazy-string-encoding lazy-string
3209 Return the encoding that will be applied to @var{lazy-string}
3210 when the string is printed by @value{GDBN}. If the encoding is not
3211 set, or contains an empty string, then @value{GDBN} will select the
3212 most appropriate encoding when the string is printed.
3215 @deffn {Scheme Procedure} lazy-string-type lazy-string
3216 Return the type that is represented by @var{lazy-string}'s type.
3217 For a lazy string this will always be a pointer type. To
3218 resolve this to the lazy string's character type, use @code{type-target-type}.
3219 @xref{Types In Guile}.
3222 @deffn {Scheme Procedure} lazy-string->value lazy-string
3223 Convert the @code{<gdb:lazy-string>} to a @code{<gdb:value>}. This value
3224 will point to the string in memory, but will lose all the delayed
3225 retrieval, encoding and handling that @value{GDBN} applies to a
3226 @code{<gdb:lazy-string>}.
3229 @node Architectures In Guile
3230 @subsubsection Guile representation of architectures
3232 @cindex guile architectures
3235 @value{GDBN} uses architecture specific parameters and artifacts in a
3236 number of its various computations. An architecture is represented
3237 by an instance of the @code{<gdb:arch>} class.
3239 The following architecture-related procedures are provided by the
3240 @code{(gdb)} module:
3242 @deffn {Scheme Procedure} arch? object
3243 Return @code{#t} if @var{object} is an object of type @code{<gdb:arch>}.
3244 Otherwise return @code{#f}.
3247 @deffn {Scheme Procedure} current-arch
3248 Return the current architecture as a @code{<gdb:arch>} object.
3251 @deffn {Scheme Procedure} arch-name arch
3252 Return the name (string value) of @code{<gdb:arch>} @var{arch}.
3255 @deffn {Scheme Procedure} arch-charset arch
3256 Return name of target character set of @code{<gdb:arch>} @var{arch}.
3259 @deffn {Scheme Procedure} arch-wide-charset
3260 Return name of target wide character set of @code{<gdb:arch>} @var{arch}.
3263 Each architecture provides a set of predefined types, obtained by
3264 the following functions.
3266 @deffn {Scheme Procedure} arch-void-type arch
3267 Return the @code{<gdb:type>} object for a @code{void} type
3268 of architecture @var{arch}.
3271 @deffn {Scheme Procedure} arch-char-type arch
3272 Return the @code{<gdb:type>} object for a @code{char} type
3273 of architecture @var{arch}.
3276 @deffn {Scheme Procedure} arch-short-type arch
3277 Return the @code{<gdb:type>} object for a @code{short} type
3278 of architecture @var{arch}.
3281 @deffn {Scheme Procedure} arch-int-type arch
3282 Return the @code{<gdb:type>} object for an @code{int} type
3283 of architecture @var{arch}.
3286 @deffn {Scheme Procedure} arch-long-type arch
3287 Return the @code{<gdb:type>} object for a @code{long} type
3288 of architecture @var{arch}.
3291 @deffn {Scheme Procedure} arch-schar-type arch
3292 Return the @code{<gdb:type>} object for a @code{signed char} type
3293 of architecture @var{arch}.
3296 @deffn {Scheme Procedure} arch-uchar-type arch
3297 Return the @code{<gdb:type>} object for an @code{unsigned char} type
3298 of architecture @var{arch}.
3301 @deffn {Scheme Procedure} arch-ushort-type arch
3302 Return the @code{<gdb:type>} object for an @code{unsigned short} type
3303 of architecture @var{arch}.
3306 @deffn {Scheme Procedure} arch-uint-type arch
3307 Return the @code{<gdb:type>} object for an @code{unsigned int} type
3308 of architecture @var{arch}.
3311 @deffn {Scheme Procedure} arch-ulong-type arch
3312 Return the @code{<gdb:type>} object for an @code{unsigned long} type
3313 of architecture @var{arch}.
3316 @deffn {Scheme Procedure} arch-float-type arch
3317 Return the @code{<gdb:type>} object for a @code{float} type
3318 of architecture @var{arch}.
3321 @deffn {Scheme Procedure} arch-double-type arch
3322 Return the @code{<gdb:type>} object for a @code{double} type
3323 of architecture @var{arch}.
3326 @deffn {Scheme Procedure} arch-longdouble-type arch
3327 Return the @code{<gdb:type>} object for a @code{long double} type
3328 of architecture @var{arch}.
3331 @deffn {Scheme Procedure} arch-bool-type arch
3332 Return the @code{<gdb:type>} object for a @code{bool} type
3333 of architecture @var{arch}.
3336 @deffn {Scheme Procedure} arch-longlong-type arch
3337 Return the @code{<gdb:type>} object for a @code{long long} type
3338 of architecture @var{arch}.
3341 @deffn {Scheme Procedure} arch-ulonglong-type arch
3342 Return the @code{<gdb:type>} object for an @code{unsigned long long} type
3343 of architecture @var{arch}.
3346 @deffn {Scheme Procedure} arch-int8-type arch
3347 Return the @code{<gdb:type>} object for an @code{int8} type
3348 of architecture @var{arch}.
3351 @deffn {Scheme Procedure} arch-uint8-type arch
3352 Return the @code{<gdb:type>} object for a @code{uint8} type
3353 of architecture @var{arch}.
3356 @deffn {Scheme Procedure} arch-int16-type arch
3357 Return the @code{<gdb:type>} object for an @code{int16} type
3358 of architecture @var{arch}.
3361 @deffn {Scheme Procedure} arch-uint16-type arch
3362 Return the @code{<gdb:type>} object for a @code{uint16} type
3363 of architecture @var{arch}.
3366 @deffn {Scheme Procedure} arch-int32-type arch
3367 Return the @code{<gdb:type>} object for an @code{int32} type
3368 of architecture @var{arch}.
3371 @deffn {Scheme Procedure} arch-uint32-type arch
3372 Return the @code{<gdb:type>} object for a @code{uint32} type
3373 of architecture @var{arch}.
3376 @deffn {Scheme Procedure} arch-int64-type arch
3377 Return the @code{<gdb:type>} object for an @code{int64} type
3378 of architecture @var{arch}.
3381 @deffn {Scheme Procedure} arch-uint64-type arch
3382 Return the @code{<gdb:type>} object for a @code{uint64} type
3383 of architecture @var{arch}.
3389 (gdb) guile (type-name (arch-uchar-type (current-arch)))
3393 @node Disassembly In Guile
3394 @subsubsection Disassembly In Guile
3396 The disassembler can be invoked from Scheme code.
3397 Furthermore, the disassembler can take a Guile port as input,
3398 allowing one to disassemble from any source, and not just target memory.
3400 @c TODO: line length
3401 @deffn {Scheme Procedure} arch-disassemble arch start-pc @r{[}#:port port@r{]} @r{[}#:offset offset@r{]} @r{[}#:size size@r{]} @r{[}#:count count@r{]}
3402 Return a list of disassembled instructions starting from the memory
3403 address @var{start-pc}.
3405 The optional argument @var{port} specifies the input port to read bytes from.
3406 If @var{port} is @code{#f} then bytes are read from target memory.
3408 The optional argument @var{offset} specifies the address offset of the
3409 first byte in @var{port}. This is useful, for example, when @var{port}
3410 specifies a @samp{bytevector} and you want the bytevector to be disassembled
3411 as if it came from that address. The @var{start-pc} passed to the reader
3412 for @var{port} is offset by the same amount.
3416 (gdb) guile (use-modules (rnrs io ports))
3417 (gdb) guile (define pc (value->integer (parse-and-eval "$pc")))
3418 (gdb) guile (define mem (open-memory #:start pc))
3419 (gdb) guile (define bv (get-bytevector-n mem 10))
3420 (gdb) guile (define bv-port (open-bytevector-input-port bv))
3421 (gdb) guile (define arch (current-arch))
3422 (gdb) guile (arch-disassemble arch pc #:port bv-port #:offset pc)
3423 (((address . 4195516) (asm . "mov $0x4005c8,%edi") (length . 5)))
3426 The optional arguments @var{size} and
3427 @var{count} determine the number of instructions in the returned list.
3428 If either @var{size} or @var{count} is specified as zero, then
3429 no instructions are disassembled and an empty list is returned.
3430 If both the optional arguments @var{size} and @var{count} are
3431 specified, then a list of at most @var{count} disassembled instructions
3432 whose start address falls in the closed memory address interval from
3433 @var{start-pc} to (@var{start-pc} + @var{size} - 1) are returned.
3434 If @var{size} is not specified, but @var{count} is specified,
3435 then @var{count} number of instructions starting from the address
3436 @var{start-pc} are returned. If @var{count} is not specified but
3437 @var{size} is specified, then all instructions whose start address
3438 falls in the closed memory address interval from @var{start-pc} to
3439 (@var{start-pc} + @var{size} - 1) are returned.
3440 If neither @var{size} nor @var{count} are specified, then a single
3441 instruction at @var{start-pc} is returned.
3443 Each element of the returned list is an alist (associative list)
3444 with the following keys:
3449 The value corresponding to this key is a Guile integer of
3450 the memory address of the instruction.
3453 The value corresponding to this key is a string value which represents
3454 the instruction with assembly language mnemonics. The assembly
3455 language flavor used is the same as that specified by the current CLI
3456 variable @code{disassembly-flavor}. @xref{Machine Code}.
3459 The value corresponding to this key is the length of the instruction in bytes.
3464 @node I/O Ports in Guile
3465 @subsubsection I/O Ports in Guile
3467 @deffn {Scheme Procedure} input-port
3468 Return @value{GDBN}'s input port as a Guile port object.
3471 @deffn {Scheme Procedure} output-port
3472 Return @value{GDBN}'s output port as a Guile port object.
3475 @deffn {Scheme Procedure} error-port
3476 Return @value{GDBN}'s error port as a Guile port object.
3479 @deffn {Scheme Procedure} stdio-port? object
3480 Return @code{#t} if @var{object} is a @value{GDBN} stdio port.
3481 Otherwise return @code{#f}.
3484 @node Memory Ports in Guile
3485 @subsubsection Memory Ports in Guile
3487 @value{GDBN} provides a @code{port} interface to target memory.
3488 This allows Guile code to read/write target memory using Guile's port and
3489 bytevector functionality. The main routine is @code{open-memory} which
3490 returns a port object. One can then read/write memory using that object.
3492 @deffn {Scheme Procedure} open-memory @r{[}#:mode mode{]} @r{[}#:start address{]} @r{[}#:size size{]}
3493 Return a port object that can be used for reading and writing memory.
3494 The port will be open according to @var{mode}, which is the standard
3495 mode argument to Guile port open routines, except that it is
3496 restricted to one of @samp{"r"}, @samp{"w"}, or @samp{"r+"}. For
3497 compatibility @samp{"b"} (binary) may also be present, but we ignore
3498 it: memory ports are binary only. The default is @samp{"r"},
3501 The chunk of memory that can be accessed can be bounded.
3502 If both @var{start} and @var{size} are unspecified, all of memory can be
3503 accessed. If only @var{start} is specified, all of memory from that point
3504 on can be accessed. If only @var{size} if specified, all memory in the
3505 range [0,@var{size}) can be accessed. If both are specified, all memory
3506 in the rane [@var{start},@var{start}+@var{size}) can be accessed.
3509 @deffn {Scheme Procedure} memory-port?
3510 Return @code{#t} if @var{object} is an object of type @code{<gdb:memory-port>}.
3511 Otherwise return @code{#f}.
3514 @deffn {Scheme Procedure} memory-port-range memory-port
3515 Return the range of @code{<gdb:memory-port>} @var{memory-port} as a list
3516 of two elements: @code{(start end)}. The range is @var{start} to @var{end}
3520 @deffn {Scheme Procedure} memory-port-read-buffer-size memory-port
3521 Return the size of the read buffer of @code{<gdb:memory-port>}
3525 @deffn {Scheme Procedure} set-memory-port-read-buffer-size! memory-port size
3526 Set the size of the read buffer of @code{<gdb:memory-port>}
3527 @var{memory-port} to @var{size}. The result is unspecified.
3530 @deffn {Scheme Procedure} memory-port-write-buffer-size memory-port
3531 Return the size of the write buffer of @code{<gdb:memory-port>}
3535 @deffn {Scheme Procedure} set-memory-port-write-buffer-size! memory-port size
3536 Set the size of the write buffer of @code{<gdb:memory-port>}
3537 @var{memory-port} to @var{size}. The result is unspecified.
3540 A memory port is closed like any other port, with @code{close-port}.
3542 Combined with Guile's @code{bytevectors}, memory ports provide a lot
3543 of utility. For example, to fill a buffer of 10 integers in memory,
3544 one can do something like the following.
3547 ;; In the program: int buffer[10];
3548 (use-modules (rnrs bytevectors))
3549 (use-modules (rnrs io ports))
3550 (define addr (parse-and-eval "buffer"))
3552 (define byte-size (* n 4))
3553 (define mem-port (open-memory #:mode "r+" #:start
3554 (value->integer addr) #:size byte-size))
3555 (define byte-vec (make-bytevector byte-size))
3558 (bytevector-s32-native-set! byte-vec (* i 4) (* i 42)))
3559 (put-bytevector mem-port byte-vec)
3560 (close-port mem-port)
3563 @node Iterators In Guile
3564 @subsubsection Iterators In Guile
3566 @cindex guile iterators
3567 @tindex <gdb:iterator>
3569 A simple iterator facility is provided to allow, for example,
3570 iterating over the set of program symbols without having to first
3571 construct a list of all of them. A useful contribution would be
3572 to add support for SRFI 41 and SRFI 45.
3574 @deffn {Scheme Procedure} make-iterator object progress next!
3575 A @code{<gdb:iterator>} object is constructed with the @code{make-iterator}
3576 procedure. It takes three arguments: the object to be iterated over,
3577 an object to record the progress of the iteration, and a procedure to
3578 return the next element in the iteration, or an implementation chosen value
3579 to denote the end of iteration.
3581 By convention, end of iteration is marked with @code{(end-of-iteration)},
3582 and may be tested with the @code{end-of-iteration?} predicate.
3583 The result of @code{(end-of-iteration)} is chosen so that it is not
3584 otherwise used by the @code{(gdb)} module. If you are using
3585 @code{<gdb:iterator>} in your own code it is your responsibility to
3586 maintain this invariant.
3588 A trivial example for illustration's sake:
3591 (use-modules (gdb iterator))
3592 (define my-list (list 1 2 3))
3594 (make-iterator my-list my-list
3596 (let ((l (iterator-progress iter)))
3600 (set-iterator-progress! iter (cdr l))
3604 Here is a slightly more realistic example, which computes a list of all the
3605 functions in @code{my-global-block}.
3608 (use-modules (gdb iterator))
3609 (define this-sal (find-pc-line (frame-pc (selected-frame))))
3610 (define this-symtab (sal-symtab this-sal))
3611 (define this-global-block (symtab-global-block this-symtab))
3612 (define syms-iter (make-block-symbols-iterator this-global-block))
3613 (define functions (iterator-filter symbol-function? syms-iter))
3617 @deffn {Scheme Procedure} iterator? object
3618 Return @code{#t} if @var{object} is a @code{<gdb:iterator>} object.
3619 Otherwise return @code{#f}.
3622 @deffn {Scheme Procedure} iterator-object iterator
3623 Return the first argument that was passed to @code{make-iterator}.
3624 This is the object being iterated over.
3627 @deffn {Scheme Procedure} iterator-progress iterator
3628 Return the object tracking iteration progress.
3631 @deffn {Scheme Procedure} set-iterator-progress! iterator new-value
3632 Set the object tracking iteration progress.
3635 @deffn {Scheme Procedure} iterator-next! iterator
3636 Invoke the procedure that was the third argument to @code{make-iterator},
3637 passing it one argument, the @code{<gdb:iterator>} object.
3638 The result is either the next element in the iteration, or an end
3639 marker as implemented by the @code{next!} procedure.
3640 By convention the end marker is the result of @code{(end-of-iteration)}.
3643 @deffn {Scheme Procedure} end-of-iteration
3644 Return the Scheme object that denotes end of iteration.
3647 @deffn {Scheme Procedure} end-of-iteration? object
3648 Return @code{#t} if @var{object} is the end of iteration marker.
3649 Otherwise return @code{#f}.
3652 These functions are provided by the @code{(gdb iterator)} module to
3653 assist in using iterators.
3655 @deffn {Scheme Procedure} make-list-iterator list
3656 Return a @code{<gdb:iterator>} object that will iterate over @var{list}.
3659 @deffn {Scheme Procedure} iterator->list iterator
3660 Return the elements pointed to by @var{iterator} as a list.
3663 @deffn {Scheme Procedure} iterator-map proc iterator
3664 Return the list of objects obtained by applying @var{proc} to the object
3665 pointed to by @var{iterator} and to each subsequent object.
3668 @deffn {Scheme Procedure} iterator-for-each proc iterator
3669 Apply @var{proc} to each element pointed to by @var{iterator}.
3670 The result is unspecified.
3673 @deffn {Scheme Procedure} iterator-filter pred iterator
3674 Return the list of elements pointed to by @var{iterator} that satisfy
3678 @deffn {Scheme Procedure} iterator-until pred iterator
3679 Run @var{iterator} until the result of @code{(pred element)} is true
3680 and return that as the result. Otherwise return @code{#f}.
3683 @node Guile Auto-loading
3684 @subsection Guile Auto-loading
3685 @cindex guile auto-loading
3687 When a new object file is read (for example, due to the @code{file}
3688 command, or because the inferior has loaded a shared library),
3689 @value{GDBN} will look for Guile support scripts in two ways:
3690 @file{@var{objfile}-gdb.scm} and the @code{.debug_gdb_scripts} section.
3691 @xref{Auto-loading extensions}.
3693 The auto-loading feature is useful for supplying application-specific
3694 debugging commands and scripts.
3696 Auto-loading can be enabled or disabled,
3697 and the list of auto-loaded scripts can be printed.
3700 @anchor{set auto-load guile-scripts}
3701 @kindex set auto-load guile-scripts
3702 @item set auto-load guile-scripts [on|off]
3703 Enable or disable the auto-loading of Guile scripts.
3705 @anchor{show auto-load guile-scripts}
3706 @kindex show auto-load guile-scripts
3707 @item show auto-load guile-scripts
3708 Show whether auto-loading of Guile scripts is enabled or disabled.
3710 @anchor{info auto-load guile-scripts}
3711 @kindex info auto-load guile-scripts
3712 @cindex print list of auto-loaded Guile scripts
3713 @item info auto-load guile-scripts [@var{regexp}]
3714 Print the list of all Guile scripts that @value{GDBN} auto-loaded.
3716 Also printed is the list of Guile scripts that were mentioned in
3717 the @code{.debug_gdb_scripts} section and were not found.
3718 This is useful because their names are not printed when @value{GDBN}
3719 tries to load them and fails. There may be many of them, and printing
3720 an error message for each one is problematic.
3722 If @var{regexp} is supplied only Guile scripts with matching names are printed.
3727 (gdb) info auto-load guile-scripts
3729 Yes scm-section-script.scm
3730 full name: /tmp/scm-section-script.scm
3731 No my-foo-pretty-printers.scm
3735 When reading an auto-loaded file, @value{GDBN} sets the
3736 @dfn{current objfile}. This is available via the @code{current-objfile}
3737 procedure (@pxref{Objfiles In Guile}). This can be useful for
3738 registering objfile-specific pretty-printers.
3741 @subsection Guile Modules
3742 @cindex guile modules
3744 @value{GDBN} comes with several modules to assist writing Guile code.
3747 * Guile Printing Module:: Building and registering pretty-printers
3748 * Guile Types Module:: Utilities for working with types
3751 @node Guile Printing Module
3752 @subsubsection Guile Printing Module
3754 This module provides a collection of utilities for working with
3760 (use-modules (gdb printing))
3763 @deffn {Scheme Procedure} prepend-pretty-printer! object printer
3764 Add @var{printer} to the front of the list of pretty-printers for
3765 @var{object}. The @var{object} must either be a @code{<gdb:objfile>} object,
3766 or @code{#f} in which case @var{printer} is added to the global list of
3770 @deffn {Scheme Procecure} append-pretty-printer! object printer
3771 Add @var{printer} to the end of the list of pretty-printers for
3772 @var{object}. The @var{object} must either be a @code{<gdb:objfile>} object,
3773 or @code{#f} in which case @var{printer} is added to the global list of
3777 @node Guile Types Module
3778 @subsubsection Guile Types Module
3780 This module provides a collection of utilities for working with
3781 @code{<gdb:type>} objects.
3786 (use-modules (gdb types))
3789 @deffn {Scheme Procedure} get-basic-type type
3790 Return @var{type} with const and volatile qualifiers stripped,
3791 and with typedefs and C@t{++} references converted to the underlying type.
3796 typedef const int const_int;
3798 const_int& foo_ref (foo);
3799 int main () @{ return 0; @}
3806 (gdb) guile (use-modules (gdb) (gdb types))
3807 (gdb) guile (define foo-ref (parse-and-eval "foo_ref"))
3808 (gdb) guile (get-basic-type (value-type foo-ref))
3813 @deffn {Scheme Procedure} type-has-field-deep? type field
3814 Return @code{#t} if @var{type}, assumed to be a type with fields
3815 (e.g., a structure or union), has field @var{field}.
3816 Otherwise return @code{#f}.
3817 This searches baseclasses, whereas @code{type-has-field?} does not.
3820 @deffn {Scheme Procedure} make-enum-hashtable enum-type
3821 Return a Guile hash table produced from @var{enum-type}.
3822 Elements in the hash table are referenced with @code{hashq-ref}.