Known problems in GDB 6.2 See also: http://www.gnu.org/software/gdb/bugs/ *** Build problems build/1458: compile failed on hpux11 GDB has build problems on HP/UX 11 with some versions of the HP Ansi C compiler. (GCC works fine). The problem happens when compiling intl/bindtextdom.c. The error is: cc: "gettextP.h", line 50: error 1000: Unexpected symbol: "SWAP". cc: panic 2017: Cannot recover from earlier errors, terminating. *** Error exit code 1 This is a problem with the 'inline' keyword in gettextP.h. The workaround is to disable 'inline' before building gdb: export ac_cv_c_inline=no This problem happens only with some versions of the HP Ansi C compiler. Versions A.11.01.25171.GP and B.11.11.28706.GP have both been observed to work; version B.11.11.04 gets the build error and needs the workaround. This problem might also happen with other C compilers. *** Misc gdb/1560: Control-C does not always interrupt GDB. When GDB is busy processing a command which takes a long time to complete, hitting Control-C does not have the expected effect. The command execution is not aborted, and the "QUIT" message confirming the abortion is displayed only after the command has been completed. *** C++ support gdb/931: GDB could be more generous when reading types C++ templates on input When the user types a template, GDB frequently requires the type to be typed in a certain way (e.g. "const char*" as opposed to "const char *" or "char const *" or "char const*"). gdb/1512: no canonical way to output names of C++ types We currently don't have any canonical way to output names of C++ types. E.g. "const char *" versus "char const *"; more subtleties arise when dealing with templates. gdb/1516: [regression] local classes, gcc 2.95.3, dwarf-2 With gcc 2.95.3 and the dwarf-2 debugging format, classes which are defined locally to a function include the demangled name of the function as part of their name. For example, if a function "foobar" contains a local class definition "Local", gdb will say that the name of the class type is "foobar__Fi.0:Local". This applies only to classes where the class type is defined inside a function, not to variables defined with types that are defined somewhere outside any function (which most types are). gdb/1588: names of c++ nested types in casts must be enclosed in quotes You must type (gdb) print ('Foo::Bar') x or (gdb) print ('Foo::Bar' *) y instead of (gdb) print (Foo::Bar) x or (gdb) print (Foo::Bar *) y respectively. gdb/1091: Constructor breakpoints ignored gdb/1193: g++ 3.3 creates multiple constructors: gdb 5.3 can't set breakpoints When gcc 3.x compiles a C++ constructor or C++ destructor, it generates 2 or 3 different versions of the object code. These versions have unique mangled names (they have to, in order for linking to work), but they have identical source code names, which leads to a great deal of confusion. Specifically, if you set a breakpoint in a constructor or a destructor, gdb will put a breakpoint in one of the versions, but your program may execute the other version. This makes it impossible to set breakpoints reliably in constructors or destructors. gcc 3.x generates these multiple object code functions in order to implement virtual base classes. gcc 2.x generated just one object code function with a hidden parameter, but gcc 3.x conforms to a multi-vendor ABI for C++ which requires multiple object code functions. *** Signal handlers On many systems an attempt to single-step a system-call instruction results in two or more instructions being executed (the system-call, and one or more instructions following). When attempting to single-step through a signal trampoline, this problem may result the program unintentionally running to completion, or re-execute the faulting instruction, or even corrupting the program counter. Ref: PR breakpoints/1702. *** Stack backtraces GDB's core code base has been updated to use a new backtrace mechanism. This mechanism makes it possible to support new features such DWARF 2 Call Frame Information (which in turn makes possible backtraces through optimized code). Since this code is new, it is known to still have a few problems: gdb/1505: [regression] gdb prints a bad backtrace for a thread When backtracing a thread, gdb does not stop when it reaches the outermost frame, instead continuing until it hits garbage. This is sensitive to the operating system and thread library. *** Threads threads/1650: manythreads.exp A program which creates many threads which exit very quickly (hundreds of thousands of threads in the test program) can cause gdb to generate an internal error. The internal error often looks like: lin-lwp.c:744: internal-error: stop_callback: Assertion `lp->status == 0' failed. A problem internal to GDB has been detected. further debugging may prove unreliable. Quit this debugging session? (y or n) This has been observed on native i686-pc-linux-gnu with linuxthreads, the old threading model. With NPTL threads, this internal error has not been observed.