1 // Copyright (c) 2006, Google Inc.
2 // All rights reserved.
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5 // modification, are permitted provided that the following conditions are
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31 // Revamped and reorganized by Craig Silverstein
33 // This is the file that should be included by any file which declares
34 // or defines a command line flag or wants to parse command line flags
35 // or print a program usage message (which will include information about
36 // flags). Executive summary, in the form of an example foo.cc file:
38 // #include "foo.h" // foo.h has a line "DECLARE_int32(start);"
39 // #include "validators.h" // hypothetical file defining ValidateIsFile()
41 // DEFINE_int32(end, 1000, "The last record to read");
43 // DEFINE_string(filename, "my_file.txt", "The file to read");
44 // // Crash if the specified file does not exist.
45 // static bool dummy = RegisterFlagValidator(&FLAGS_filename,
48 // DECLARE_bool(verbose); // some other file has a DEFINE_bool(verbose, ...)
51 // if (FLAGS_verbose) printf("Records %d-%d\n", FLAGS_start, FLAGS_end);
54 // Then, at the command-line:
55 // ./foo --noverbose --start=5 --end=100
57 // For more details, see
60 // --- A note about thread-safety:
62 // We describe many functions in this routine as being thread-hostile,
63 // thread-compatible, or thread-safe. Here are the meanings we use:
65 // thread-safe: it is safe for multiple threads to call this routine
66 // (or, when referring to a class, methods of this class)
68 // thread-hostile: it is not safe for multiple threads to call this
69 // routine (or methods of this class) concurrently. In gflags,
70 // most thread-hostile routines are intended to be called early in,
71 // or even before, main() -- that is, before threads are spawned.
72 // thread-compatible: it is safe for multiple threads to read from
73 // this variable (when applied to variables), or to call const
74 // methods of this class (when applied to classes), as long as no
75 // other thread is writing to the variable or calling non-const
76 // methods of this class.
78 #ifndef GFLAGS_GFLAGS_H_
79 #define GFLAGS_GFLAGS_H_
84 #include "gflags/gflags_declare.h" // IWYU pragma: export
87 // We always want to export variables defined in user code
88 #ifndef GFLAGS_DLL_DEFINE_FLAG
89 # if GFLAGS_IS_A_DLL && defined(_MSC_VER)
90 # define GFLAGS_DLL_DEFINE_FLAG __declspec(dllexport)
92 # define GFLAGS_DLL_DEFINE_FLAG
97 namespace GFLAGS_NAMESPACE {
100 // --------------------------------------------------------------------
101 // To actually define a flag in a file, use DEFINE_bool,
102 // DEFINE_string, etc. at the bottom of this file. You may also find
103 // it useful to register a validator with the flag. This ensures that
104 // when the flag is parsed from the commandline, or is later set via
105 // SetCommandLineOption, we call the validation function. It is _not_
106 // called when you assign the value to the flag directly using the = operator.
108 // The validation function should return true if the flag value is valid, and
109 // false otherwise. If the function returns false for the new setting of the
110 // flag, the flag will retain its current value. If it returns false for the
111 // default value, ParseCommandLineFlags() will die.
113 // This function is safe to call at global construct time (as in the
117 // static bool ValidatePort(const char* flagname, int32 value) {
118 // if (value > 0 && value < 32768) // value is ok
120 // printf("Invalid value for --%s: %d\n", flagname, (int)value);
123 // DEFINE_int32(port, 0, "What port to listen on");
124 // static bool dummy = RegisterFlagValidator(&FLAGS_port, &ValidatePort);
126 // Returns true if successfully registered, false if not (because the
127 // first argument doesn't point to a command-line flag, or because a
128 // validator is already registered for this flag).
129 extern GFLAGS_DLL_DECL bool RegisterFlagValidator(const bool* flag, bool (*validate_fn)(const char*, bool));
130 extern GFLAGS_DLL_DECL bool RegisterFlagValidator(const int32* flag, bool (*validate_fn)(const char*, int32));
131 extern GFLAGS_DLL_DECL bool RegisterFlagValidator(const uint32* flag, bool (*validate_fn)(const char*, uint32));
132 extern GFLAGS_DLL_DECL bool RegisterFlagValidator(const int64* flag, bool (*validate_fn)(const char*, int64));
133 extern GFLAGS_DLL_DECL bool RegisterFlagValidator(const uint64* flag, bool (*validate_fn)(const char*, uint64));
134 extern GFLAGS_DLL_DECL bool RegisterFlagValidator(const double* flag, bool (*validate_fn)(const char*, double));
135 extern GFLAGS_DLL_DECL bool RegisterFlagValidator(const std::string* flag, bool (*validate_fn)(const char*, const std::string&));
137 // Convenience macro for the registration of a flag validator
138 #define DEFINE_validator(name, validator) \
139 static const bool name##_validator_registered = \
140 GFLAGS_NAMESPACE::RegisterFlagValidator(&FLAGS_##name, validator)
143 // --------------------------------------------------------------------
144 // These methods are the best way to get access to info about the
145 // list of commandline flags. Note that these routines are pretty slow.
146 // GetAllFlags: mostly-complete info about the list, sorted by file.
147 // ShowUsageWithFlags: pretty-prints the list to stdout (what --help does)
148 // ShowUsageWithFlagsRestrict: limit to filenames with restrict as a substr
150 // In addition to accessing flags, you can also access argv[0] (the program
151 // name) and argv (the entire commandline), which we sock away a copy of.
152 // These variables are static, so you should only set them once.
154 // No need to export this data only structure from DLL, avoiding VS warning 4251.
155 struct CommandLineFlagInfo {
156 std::string name; // the name of the flag
157 std::string type; // the type of the flag: int32, etc
158 std::string description; // the "help text" associated with the flag
159 std::string current_value; // the current value, as a string
160 std::string default_value; // the default value, as a string
161 std::string filename; // 'cleaned' version of filename holding the flag
162 bool has_validator_fn; // true if RegisterFlagValidator called on this flag
163 bool is_default; // true if the flag has the default value and
164 // has not been set explicitly from the cmdline
165 // or via SetCommandLineOption
166 const void* flag_ptr; // pointer to the flag's current value (i.e. FLAGS_foo)
169 // Using this inside of a validator is a recipe for a deadlock.
170 // TODO(user) Fix locking when validators are running, to make it safe to
171 // call validators during ParseAllFlags.
172 // Also make sure then to uncomment the corresponding unit test in
173 // gflags_unittest.sh
174 extern GFLAGS_DLL_DECL void GetAllFlags(std::vector<CommandLineFlagInfo>* OUTPUT);
175 // These two are actually defined in gflags_reporting.cc.
176 extern GFLAGS_DLL_DECL void ShowUsageWithFlags(const char *argv0); // what --help does
177 extern GFLAGS_DLL_DECL void ShowUsageWithFlagsRestrict(const char *argv0, const char *restrict);
179 // Create a descriptive string for a flag.
180 // Goes to some trouble to make pretty line breaks.
181 extern GFLAGS_DLL_DECL std::string DescribeOneFlag(const CommandLineFlagInfo& flag);
183 // Thread-hostile; meant to be called before any threads are spawned.
184 extern GFLAGS_DLL_DECL void SetArgv(int argc, const char** argv);
186 // The following functions are thread-safe as long as SetArgv() is
187 // only called before any threads start.
188 extern GFLAGS_DLL_DECL const std::vector<std::string>& GetArgvs();
189 extern GFLAGS_DLL_DECL const char* GetArgv(); // all of argv as a string
190 extern GFLAGS_DLL_DECL const char* GetArgv0(); // only argv0
191 extern GFLAGS_DLL_DECL uint32 GetArgvSum(); // simple checksum of argv
192 extern GFLAGS_DLL_DECL const char* ProgramInvocationName(); // argv0, or "UNKNOWN" if not set
193 extern GFLAGS_DLL_DECL const char* ProgramInvocationShortName(); // basename(argv0)
195 // ProgramUsage() is thread-safe as long as SetUsageMessage() is only
196 // called before any threads start.
197 extern GFLAGS_DLL_DECL const char* ProgramUsage(); // string set by SetUsageMessage()
199 // VersionString() is thread-safe as long as SetVersionString() is only
200 // called before any threads start.
201 extern GFLAGS_DLL_DECL const char* VersionString(); // string set by SetVersionString()
205 // --------------------------------------------------------------------
206 // Normally you access commandline flags by just saying "if (FLAGS_foo)"
207 // or whatever, and set them by calling "FLAGS_foo = bar" (or, more
208 // commonly, via the DEFINE_foo macro). But if you need a bit more
209 // control, we have programmatic ways to get/set the flags as well.
210 // These programmatic ways to access flags are thread-safe, but direct
211 // access is only thread-compatible.
213 // Return true iff the flagname was found.
214 // OUTPUT is set to the flag's value, or unchanged if we return false.
215 extern GFLAGS_DLL_DECL bool GetCommandLineOption(const char* name, std::string* OUTPUT);
217 // Return true iff the flagname was found. OUTPUT is set to the flag's
218 // CommandLineFlagInfo or unchanged if we return false.
219 extern GFLAGS_DLL_DECL bool GetCommandLineFlagInfo(const char* name, CommandLineFlagInfo* OUTPUT);
221 // Return the CommandLineFlagInfo of the flagname. exit() if name not found.
222 // Example usage, to check if a flag's value is currently the default value:
223 // if (GetCommandLineFlagInfoOrDie("foo").is_default) ...
224 extern GFLAGS_DLL_DECL CommandLineFlagInfo GetCommandLineFlagInfoOrDie(const char* name);
226 enum GFLAGS_DLL_DECL FlagSettingMode {
227 // update the flag's value (can call this multiple times).
229 // update the flag's value, but *only if* it has not yet been updated
230 // with SET_FLAGS_VALUE, SET_FLAG_IF_DEFAULT, or "FLAGS_xxx = nondef".
232 // set the flag's default value to this. If the flag has not yet updated
233 // yet (via SET_FLAGS_VALUE, SET_FLAG_IF_DEFAULT, or "FLAGS_xxx = nondef")
234 // change the flag's current value to the new default value as well.
238 // Set a particular flag ("command line option"). Returns a string
239 // describing the new value that the option has been set to. The
240 // return value API is not well-specified, so basically just depend on
241 // it to be empty if the setting failed for some reason -- the name is
242 // not a valid flag name, or the value is not a valid value -- and
245 // SetCommandLineOption uses set_mode == SET_FLAGS_VALUE (the common case)
246 extern GFLAGS_DLL_DECL std::string SetCommandLineOption (const char* name, const char* value);
247 extern GFLAGS_DLL_DECL std::string SetCommandLineOptionWithMode(const char* name, const char* value, FlagSettingMode set_mode);
250 // --------------------------------------------------------------------
251 // Saves the states (value, default value, whether the user has set
252 // the flag, registered validators, etc) of all flags, and restores
253 // them when the FlagSaver is destroyed. This is very useful in
254 // tests, say, when you want to let your tests change the flags, but
255 // make sure that they get reverted to the original states when your
262 // FLAG_bar = "some value";
264 // // test happens here. You can return at any time
265 // // without worrying about restoring the FLAG values.
268 // Note: This class is marked with GFLAGS_ATTRIBUTE_UNUSED because all
269 // the work is done in the constructor and destructor, so in the standard
270 // usage example above, the compiler would complain that it's an
273 // This class is thread-safe. However, its destructor writes to
274 // exactly the set of flags that have changed value during its
275 // lifetime, so concurrent _direct_ access to those flags
276 // (i.e. FLAGS_foo instead of {Get,Set}CommandLineOption()) is unsafe.
278 class GFLAGS_DLL_DECL FlagSaver {
284 class FlagSaverImpl* impl_; // we use pimpl here to keep API steady
286 FlagSaver(const FlagSaver&); // no copying!
287 void operator=(const FlagSaver&);
288 }@GFLAGS_ATTRIBUTE_UNUSED@;
290 // --------------------------------------------------------------------
291 // Some deprecated or hopefully-soon-to-be-deprecated functions.
293 // This is often used for logging. TODO(csilvers): figure out a better way
294 extern GFLAGS_DLL_DECL std::string CommandlineFlagsIntoString();
295 // Usually where this is used, a FlagSaver should be used instead.
296 extern GFLAGS_DLL_DECL
297 bool ReadFlagsFromString(const std::string& flagfilecontents,
298 const char* prog_name,
299 bool errors_are_fatal); // uses SET_FLAGS_VALUE
301 // These let you manually implement --flagfile functionality.
303 extern GFLAGS_DLL_DECL bool AppendFlagsIntoFile(const std::string& filename, const char* prog_name);
304 extern GFLAGS_DLL_DECL bool ReadFromFlagsFile(const std::string& filename, const char* prog_name, bool errors_are_fatal); // uses SET_FLAGS_VALUE
307 // --------------------------------------------------------------------
308 // Useful routines for initializing flags from the environment.
309 // In each case, if 'varname' does not exist in the environment
310 // return defval. If 'varname' does exist but is not valid
311 // (e.g., not a number for an int32 flag), abort with an error.
312 // Otherwise, return the value. NOTE: for booleans, for true use
313 // 't' or 'T' or 'true' or '1', for false 'f' or 'F' or 'false' or '0'.
315 extern GFLAGS_DLL_DECL bool BoolFromEnv(const char *varname, bool defval);
316 extern GFLAGS_DLL_DECL int32 Int32FromEnv(const char *varname, int32 defval);
317 extern GFLAGS_DLL_DECL uint32 Uint32FromEnv(const char *varname, uint32 defval);
318 extern GFLAGS_DLL_DECL int64 Int64FromEnv(const char *varname, int64 defval);
319 extern GFLAGS_DLL_DECL uint64 Uint64FromEnv(const char *varname, uint64 defval);
320 extern GFLAGS_DLL_DECL double DoubleFromEnv(const char *varname, double defval);
321 extern GFLAGS_DLL_DECL const char *StringFromEnv(const char *varname, const char *defval);
324 // --------------------------------------------------------------------
325 // The next two functions parse gflags from main():
327 // Set the "usage" message for this program. For example:
328 // string usage("This program does nothing. Sample usage:\n");
329 // usage += argv[0] + " <uselessarg1> <uselessarg2>";
330 // SetUsageMessage(usage);
331 // Do not include commandline flags in the usage: we do that for you!
332 // Thread-hostile; meant to be called before any threads are spawned.
333 extern GFLAGS_DLL_DECL void SetUsageMessage(const std::string& usage);
335 // Sets the version string, which is emitted with --version.
336 // For instance: SetVersionString("1.3");
337 // Thread-hostile; meant to be called before any threads are spawned.
338 extern GFLAGS_DLL_DECL void SetVersionString(const std::string& version);
341 // Looks for flags in argv and parses them. Rearranges argv to put
342 // flags first, or removes them entirely if remove_flags is true.
343 // If a flag is defined more than once in the command line or flag
344 // file, the last definition is used. Returns the index (into argv)
345 // of the first non-flag argument.
346 // See top-of-file for more details on this function.
347 #ifndef SWIG // In swig, use ParseCommandLineFlagsScript() instead.
348 extern GFLAGS_DLL_DECL uint32 ParseCommandLineFlags(int *argc, char*** argv, bool remove_flags);
352 // Calls to ParseCommandLineNonHelpFlags and then to
353 // HandleCommandLineHelpFlags can be used instead of a call to
354 // ParseCommandLineFlags during initialization, in order to allow for
355 // changing default values for some FLAGS (via
356 // e.g. SetCommandLineOptionWithMode calls) between the time of
357 // command line parsing and the time of dumping help information for
358 // the flags as a result of command line parsing. If a flag is
359 // defined more than once in the command line or flag file, the last
360 // definition is used. Returns the index (into argv) of the first
361 // non-flag argument. (If remove_flags is true, will always return 1.)
362 extern GFLAGS_DLL_DECL uint32 ParseCommandLineNonHelpFlags(int *argc, char*** argv, bool remove_flags);
364 // This is actually defined in gflags_reporting.cc.
365 // This function is misnamed (it also handles --version, etc.), but
366 // it's too late to change that now. :-(
367 extern GFLAGS_DLL_DECL void HandleCommandLineHelpFlags(); // in gflags_reporting.cc
369 // Allow command line reparsing. Disables the error normally
370 // generated when an unknown flag is found, since it may be found in a
371 // later parse. Thread-hostile; meant to be called before any threads
373 extern GFLAGS_DLL_DECL void AllowCommandLineReparsing();
375 // Reparse the flags that have not yet been recognized. Only flags
376 // registered since the last parse will be recognized. Any flag value
377 // must be provided as part of the argument using "=", not as a
378 // separate command line argument that follows the flag argument.
379 // Intended for handling flags from dynamically loaded libraries,
380 // since their flags are not registered until they are loaded.
381 extern GFLAGS_DLL_DECL void ReparseCommandLineNonHelpFlags();
383 // Clean up memory allocated by flags. This is only needed to reduce
384 // the quantity of "potentially leaked" reports emitted by memory
385 // debugging tools such as valgrind. It is not required for normal
386 // operation, or for the google perftools heap-checker. It must only
387 // be called when the process is about to exit, and all threads that
388 // might access flags are quiescent. Referencing flags after this is
389 // called will have unexpected consequences. This is not safe to run
390 // when multiple threads might be running: the function is
392 extern GFLAGS_DLL_DECL void ShutDownCommandLineFlags();
395 // --------------------------------------------------------------------
396 // Now come the command line flag declaration/definition macros that
397 // will actually be used. They're kind of hairy. A major reason
398 // for this is initialization: we want people to be able to access
399 // variables in global constructors and have that not crash, even if
400 // their global constructor runs before the global constructor here.
401 // (Obviously, we can't guarantee the flags will have the correct
402 // default value in that case, but at least accessing them is safe.)
403 // The only way to do that is have flags point to a static buffer.
404 // So we make one, using a union to ensure proper alignment, and
405 // then use placement-new to actually set up the flag with the
406 // correct default value. In the same vein, we have to worry about
407 // flag access in global destructors, so FlagRegisterer has to be
408 // careful never to destroy the flag-values it constructs.
410 // Note that when we define a flag variable FLAGS_<name>, we also
411 // preemptively define a junk variable, FLAGS_no<name>. This is to
412 // cause a link-time error if someone tries to define 2 flags with
413 // names like "logging" and "nologging". We do this because a bool
414 // flag FLAG can be set from the command line to true with a "-FLAG"
415 // argument, and to false with a "-noFLAG" argument, and so this can
416 // potentially avert confusion.
418 // We also put flags into their own namespace. It is purposefully
419 // named in an opaque way that people should have trouble typing
420 // directly. The idea is that DEFINE puts the flag in the weird
421 // namespace, and DECLARE imports the flag from there into the current
422 // namespace. The net result is to force people to use DECLARE to get
423 // access to a flag, rather than saying "extern GFLAGS_DLL_DECL bool FLAGS_whatever;"
424 // or some such instead. We want this so we can put extra
425 // functionality (like sanity-checking) in DECLARE if we want, and
426 // make sure it is picked up everywhere.
428 // We also put the type of the variable in the namespace, so that
429 // people can't DECLARE_int32 something that they DEFINE_bool'd
432 class GFLAGS_DLL_DECL FlagRegisterer {
434 // We instantiate this template ctor for all supported types,
435 // so it is possible to place implementation of the FlagRegisterer ctor in
437 // Calling this constructor with unsupported type will produce linker error.
438 template <typename FlagType>
439 FlagRegisterer(const char* name,
440 const char* help, const char* filename,
441 FlagType* current_storage, FlagType* defvalue_storage);
444 // If your application #defines STRIP_FLAG_HELP to a non-zero value
445 // before #including this file, we remove the help message from the
446 // binary file. This can reduce the size of the resulting binary
447 // somewhat, and may also be useful for security reasons.
449 extern GFLAGS_DLL_DECL const char kStrippedFlagHelp[];
452 } // namespace GFLAGS_NAMESPACE
455 #ifndef SWIG // In swig, ignore the main flag declarations
457 #if defined(STRIP_FLAG_HELP) && STRIP_FLAG_HELP > 0
458 // Need this construct to avoid the 'defined but not used' warning.
459 #define MAYBE_STRIPPED_HELP(txt) \
460 (false ? (txt) : GFLAGS_NAMESPACE::kStrippedFlagHelp)
462 #define MAYBE_STRIPPED_HELP(txt) txt
465 // Each command-line flag has two variables associated with it: one
466 // with the current value, and one with the default value. However,
467 // we have a third variable, which is where value is assigned; it's a
468 // constant. This guarantees that FLAG_##value is initialized at
469 // static initialization time (e.g. before program-start) rather than
470 // than global construction time (which is after program-start but
471 // before main), at least when 'value' is a compile-time constant. We
472 // use a small trick for the "default value" variable, and call it
473 // FLAGS_no<name>. This serves the second purpose of assuring a
474 // compile error if someone tries to define a flag named no<name>
475 // which is illegal (--foo and --nofoo both affect the "foo" flag).
476 #define DEFINE_VARIABLE(type, shorttype, name, value, help) \
477 namespace fL##shorttype { \
478 static const type FLAGS_nono##name = value; \
479 /* We always want to export defined variables, dll or no */ \
480 GFLAGS_DLL_DEFINE_FLAG type FLAGS_##name = FLAGS_nono##name; \
481 type FLAGS_no##name = FLAGS_nono##name; \
482 static GFLAGS_NAMESPACE::FlagRegisterer o_##name( \
483 #name, MAYBE_STRIPPED_HELP(help), __FILE__, \
484 &FLAGS_##name, &FLAGS_no##name); \
486 using fL##shorttype::FLAGS_##name
488 // For DEFINE_bool, we want to do the extra check that the passed-in
489 // value is actually a bool, and not a string or something that can be
490 // coerced to a bool. These declarations (no definition needed!) will
491 // help us do that, and never evaluate From, which is important.
492 // We'll use 'sizeof(IsBool(val))' to distinguish. This code requires
493 // that the compiler have different sizes for bool & double. Since
494 // this is not guaranteed by the standard, we check it with a
497 struct CompileAssert {};
498 typedef CompileAssert expected_sizeof_double_neq_sizeof_bool[
499 (sizeof(double) != sizeof(bool)) ? 1 : -1];
500 template<typename From> double GFLAGS_DLL_DECL IsBoolFlag(const From& from);
501 GFLAGS_DLL_DECL bool IsBoolFlag(bool from);
504 // Here are the actual DEFINE_*-macros. The respective DECLARE_*-macros
505 // are in a separate include, gflags_declare.h, for reducing
506 // the physical transitive size for DECLARE use.
507 #define DEFINE_bool(name, val, txt) \
509 typedef ::fLB::CompileAssert FLAG_##name##_value_is_not_a_bool[ \
510 (sizeof(::fLB::IsBoolFlag(val)) != sizeof(double))? 1: -1]; \
512 DEFINE_VARIABLE(bool, B, name, val, txt)
514 #define DEFINE_int32(name, val, txt) \
515 DEFINE_VARIABLE(GFLAGS_NAMESPACE::int32, I, \
518 #define DEFINE_uint32(name,val, txt) \
519 DEFINE_VARIABLE(GFLAGS_NAMESPACE::uint32, U, \
522 #define DEFINE_int64(name, val, txt) \
523 DEFINE_VARIABLE(GFLAGS_NAMESPACE::int64, I64, \
526 #define DEFINE_uint64(name,val, txt) \
527 DEFINE_VARIABLE(GFLAGS_NAMESPACE::uint64, U64, \
530 #define DEFINE_double(name, val, txt) \
531 DEFINE_VARIABLE(double, D, name, val, txt)
533 // Strings are trickier, because they're not a POD, so we can't
534 // construct them at static-initialization time (instead they get
535 // constructed at global-constructor time, which is much later). To
536 // try to avoid crashes in that case, we use a char buffer to store
537 // the string, which we can static-initialize, and then placement-new
538 // into it later. It's not perfect, but the best we can do.
542 inline clstring* dont_pass0toDEFINE_string(char *stringspot,
544 return new(stringspot) clstring(value);
546 inline clstring* dont_pass0toDEFINE_string(char *stringspot,
547 const clstring &value) {
548 return new(stringspot) clstring(value);
550 inline clstring* dont_pass0toDEFINE_string(char *stringspot,
553 // Auxiliary class used to explicitly call destructor of string objects
554 // allocated using placement new during static program deinitialization.
555 // The destructor MUST be an inline function such that the explicit
556 // destruction occurs in the same compilation unit as the placement new.
557 class StringFlagDestructor {
558 void *current_storage_;
559 void *defvalue_storage_;
563 StringFlagDestructor(void *current, void *defvalue)
564 : current_storage_(current), defvalue_storage_(defvalue) {}
566 ~StringFlagDestructor() {
567 reinterpret_cast<clstring*>(current_storage_ )->~clstring();
568 reinterpret_cast<clstring*>(defvalue_storage_)->~clstring();
574 // We need to define a var named FLAGS_no##name so people don't define
575 // --string and --nostring. And we need a temporary place to put val
576 // so we don't have to evaluate it twice. Two great needs that go
578 // The weird 'using' + 'extern' inside the fLS namespace is to work around
579 // an unknown compiler bug/issue with the gcc 4.2.1 on SUSE 10. See
580 // http://code.google.com/p/google-gflags/issues/detail?id=20
581 #define DEFINE_string(name, val, txt) \
583 using ::fLS::clstring; \
584 using ::fLS::StringFlagDestructor; \
585 static union { void* align; char s[sizeof(clstring)]; } s_##name[2]; \
586 clstring* const FLAGS_no##name = ::fLS:: \
587 dont_pass0toDEFINE_string(s_##name[0].s, \
589 static GFLAGS_NAMESPACE::FlagRegisterer o_##name( \
590 #name, MAYBE_STRIPPED_HELP(txt), __FILE__, \
591 FLAGS_no##name, new (s_##name[1].s) clstring(*FLAGS_no##name)); \
592 static StringFlagDestructor d_##name(s_##name[0].s, s_##name[1].s); \
593 extern GFLAGS_DLL_DEFINE_FLAG clstring& FLAGS_##name; \
594 using fLS::FLAGS_##name; \
595 clstring& FLAGS_##name = *FLAGS_no##name; \
597 using fLS::FLAGS_##name
602 @INCLUDE_GFLAGS_NS_H@
605 #endif // GFLAGS_GFLAGS_H_