1/* GLIB - Library of useful routines for C programming
2 * Copyright (C) 1995-1997 Peter Mattis, Spencer Kimball and Josh MacDonald
3 *
4 * This library is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Lesser General Public
6 * License as published by the Free Software Foundation; either
7 * version 2.1 of the License, or (at your option) any later version.
8 *
9 * This library is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * Lesser General Public License for more details.
13 *
14 * You should have received a copy of the GNU Lesser General Public
15 * License along with this library; if not, see <http://www.gnu.org/licenses/>.
16 */
17
18/*
19 * Modified by the GLib Team and others 1997-2000. See the AUTHORS
20 * file for a list of people on the GLib Team. See the ChangeLog
21 * files for a list of changes. These files are distributed with
22 * GLib at ftp://ftp.gtk.org/pub/gtk/.
23 */
24
25#ifndef __G_MESSAGES_H__
26#define __G_MESSAGES_H__
27
28#if !defined (__GLIB_H_INSIDE__) && !defined (GLIB_COMPILATION)
29#error "Only <glib.h> can be included directly."
30#endif
31
32#include <stdarg.h>
33#include <glib/gatomic.h>
34#include <glib/gtypes.h>
35#include <glib/gmacros.h>
36#include <glib/gvariant.h>
37
38G_BEGIN_DECLS
39
40/* calculate a string size, guaranteed to fit format + args.
41 */
42GLIB_AVAILABLE_IN_ALL
43gsize g_printf_string_upper_bound (const gchar* format,
44 va_list args) G_GNUC_PRINTF(1, 0);
45
46/* Log level shift offset for user defined
47 * log levels (0-7 are used by GLib).
48 */
49#define G_LOG_LEVEL_USER_SHIFT (8)
50
51/* Glib log levels and flags.
52 */
53typedef enum
54{
55 /* log flags */
56 G_LOG_FLAG_RECURSION = 1 << 0,
57 G_LOG_FLAG_FATAL = 1 << 1,
58
59 /* GLib log levels */
60 G_LOG_LEVEL_ERROR = 1 << 2, /* always fatal */
61 G_LOG_LEVEL_CRITICAL = 1 << 3,
62 G_LOG_LEVEL_WARNING = 1 << 4,
63 G_LOG_LEVEL_MESSAGE = 1 << 5,
64 G_LOG_LEVEL_INFO = 1 << 6,
65 G_LOG_LEVEL_DEBUG = 1 << 7,
66
67 G_LOG_LEVEL_MASK = ~(G_LOG_FLAG_RECURSION | G_LOG_FLAG_FATAL)
68} GLogLevelFlags;
69
70/* GLib log levels that are considered fatal by default */
71#define G_LOG_FATAL_MASK (G_LOG_FLAG_RECURSION | G_LOG_LEVEL_ERROR)
72
73typedef void (*GLogFunc) (const gchar *log_domain,
74 GLogLevelFlags log_level,
75 const gchar *message,
76 gpointer user_data);
77
78/* Logging mechanism
79 */
80GLIB_AVAILABLE_IN_ALL
81guint g_log_set_handler (const gchar *log_domain,
82 GLogLevelFlags log_levels,
83 GLogFunc log_func,
84 gpointer user_data);
85GLIB_AVAILABLE_IN_2_46
86guint g_log_set_handler_full (const gchar *log_domain,
87 GLogLevelFlags log_levels,
88 GLogFunc log_func,
89 gpointer user_data,
90 GDestroyNotify destroy);
91GLIB_AVAILABLE_IN_ALL
92void g_log_remove_handler (const gchar *log_domain,
93 guint handler_id);
94GLIB_AVAILABLE_IN_ALL
95void g_log_default_handler (const gchar *log_domain,
96 GLogLevelFlags log_level,
97 const gchar *message,
98 gpointer unused_data);
99GLIB_AVAILABLE_IN_ALL
100GLogFunc g_log_set_default_handler (GLogFunc log_func,
101 gpointer user_data);
102GLIB_AVAILABLE_IN_ALL
103void g_log (const gchar *log_domain,
104 GLogLevelFlags log_level,
105 const gchar *format,
106 ...) G_GNUC_PRINTF (3, 4);
107GLIB_AVAILABLE_IN_ALL
108void g_logv (const gchar *log_domain,
109 GLogLevelFlags log_level,
110 const gchar *format,
111 va_list args) G_GNUC_PRINTF(3, 0);
112GLIB_AVAILABLE_IN_ALL
113GLogLevelFlags g_log_set_fatal_mask (const gchar *log_domain,
114 GLogLevelFlags fatal_mask);
115GLIB_AVAILABLE_IN_ALL
116GLogLevelFlags g_log_set_always_fatal (GLogLevelFlags fatal_mask);
117
118/* Structured logging mechanism. */
119
120/**
121 * GLogWriterOutput:
122 * @G_LOG_WRITER_HANDLED: Log writer has handled the log entry.
123 * @G_LOG_WRITER_UNHANDLED: Log writer could not handle the log entry.
124 *
125 * Return values from #GLogWriterFuncs to indicate whether the given log entry
126 * was successfully handled by the writer, or whether there was an error in
127 * handling it (and hence a fallback writer should be used).
128 *
129 * If a #GLogWriterFunc ignores a log entry, it should return
130 * %G_LOG_WRITER_HANDLED.
131 *
132 * Since: 2.50
133 */
134typedef enum
135{
136 G_LOG_WRITER_HANDLED = 1,
137 G_LOG_WRITER_UNHANDLED = 0,
138} GLogWriterOutput;
139
140/**
141 * GLogField:
142 * @key: field name (UTF-8 string)
143 * @value: field value (arbitrary bytes)
144 * @length: length of @value, in bytes, or -1 if it is nul-terminated
145 *
146 * Structure representing a single field in a structured log entry. See
147 * g_log_structured() for details.
148 *
149 * Log fields may contain arbitrary values, including binary with embedded nul
150 * bytes. If the field contains a string, the string must be UTF-8 encoded and
151 * have a trailing nul byte. Otherwise, @length must be set to a non-negative
152 * value.
153 *
154 * Since: 2.50
155 */
156typedef struct _GLogField GLogField;
157struct _GLogField
158{
159 const gchar *key;
160 gconstpointer value;
161 gssize length;
162};
163
164/**
165 * GLogWriterFunc:
166 * @log_level: log level of the message
167 * @fields: (array length=n_fields): fields forming the message
168 * @n_fields: number of @fields
169 * @user_data: user data passed to g_log_set_writer_func()
170 *
171 * Writer function for log entries. A log entry is a collection of one or more
172 * #GLogFields, using the standard [field names from journal
173 * specification](https://www.freedesktop.org/software/systemd/man/systemd.journal-fields.html).
174 * See g_log_structured() for more information.
175 *
176 * Writer functions must ignore fields which they do not recognise, unless they
177 * can write arbitrary binary output, as field values may be arbitrary binary.
178 *
179 * @log_level is guaranteed to be included in @fields as the `PRIORITY` field,
180 * but is provided separately for convenience of deciding whether or where to
181 * output the log entry.
182 *
183 * Writer functions should return %G_LOG_WRITER_HANDLED if they handled the log
184 * message successfully or if they deliberately ignored it. If there was an
185 * error handling the message (for example, if the writer function is meant to
186 * send messages to a remote logging server and there is a network error), it
187 * should return %G_LOG_WRITER_UNHANDLED. This allows writer functions to be
188 * chained and fall back to simpler handlers in case of failure.
189 *
190 * Returns: %G_LOG_WRITER_HANDLED if the log entry was handled successfully;
191 * %G_LOG_WRITER_UNHANDLED otherwise
192 *
193 * Since: 2.50
194 */
195typedef GLogWriterOutput (*GLogWriterFunc) (GLogLevelFlags log_level,
196 const GLogField *fields,
197 gsize n_fields,
198 gpointer user_data);
199
200GLIB_AVAILABLE_IN_2_50
201void g_log_structured (const gchar *log_domain,
202 GLogLevelFlags log_level,
203 ...);
204GLIB_AVAILABLE_IN_2_50
205void g_log_structured_array (GLogLevelFlags log_level,
206 const GLogField *fields,
207 gsize n_fields);
208
209GLIB_AVAILABLE_IN_2_50
210void g_log_variant (const gchar *log_domain,
211 GLogLevelFlags log_level,
212 GVariant *fields);
213
214GLIB_AVAILABLE_IN_2_50
215void g_log_set_writer_func (GLogWriterFunc func,
216 gpointer user_data,
217 GDestroyNotify user_data_free);
218
219GLIB_AVAILABLE_IN_2_50
220gboolean g_log_writer_supports_color (gint output_fd);
221GLIB_AVAILABLE_IN_2_50
222gboolean g_log_writer_is_journald (gint output_fd);
223
224GLIB_AVAILABLE_IN_2_50
225gchar *g_log_writer_format_fields (GLogLevelFlags log_level,
226 const GLogField *fields,
227 gsize n_fields,
228 gboolean use_color);
229
230GLIB_AVAILABLE_IN_2_50
231GLogWriterOutput g_log_writer_journald (GLogLevelFlags log_level,
232 const GLogField *fields,
233 gsize n_fields,
234 gpointer user_data);
235GLIB_AVAILABLE_IN_2_50
236GLogWriterOutput g_log_writer_standard_streams (GLogLevelFlags log_level,
237 const GLogField *fields,
238 gsize n_fields,
239 gpointer user_data);
240GLIB_AVAILABLE_IN_2_50
241GLogWriterOutput g_log_writer_default (GLogLevelFlags log_level,
242 const GLogField *fields,
243 gsize n_fields,
244 gpointer user_data);
245
246GLIB_AVAILABLE_IN_2_68
247void g_log_writer_default_set_use_stderr (gboolean use_stderr);
248GLIB_AVAILABLE_IN_2_68
249gboolean g_log_writer_default_would_drop (GLogLevelFlags log_level,
250 const char *log_domain);
251
252/* G_MESSAGES_DEBUG enablement */
253GLIB_AVAILABLE_IN_2_72
254gboolean g_log_get_debug_enabled (void);
255GLIB_AVAILABLE_IN_2_72
256void g_log_set_debug_enabled (gboolean enabled);
257
258/**
259 * G_DEBUG_HERE:
260 *
261 * A convenience form of g_log_structured(), recommended to be added to
262 * functions when debugging. It prints the current monotonic time and the code
263 * location using %G_STRLOC.
264 *
265 * Since: 2.50
266 */
267#define G_DEBUG_HERE() \
268 g_log_structured (G_LOG_DOMAIN, G_LOG_LEVEL_DEBUG, \
269 "CODE_FILE", __FILE__, \
270 "CODE_LINE", G_STRINGIFY (__LINE__), \
271 "CODE_FUNC", G_STRFUNC, \
272 "MESSAGE", "%" G_GINT64_FORMAT ": %s", \
273 g_get_monotonic_time (), G_STRLOC)
274
275/* internal */
276void _g_log_fallback_handler (const gchar *log_domain,
277 GLogLevelFlags log_level,
278 const gchar *message,
279 gpointer unused_data);
280
281/* Internal functions, used to implement the following macros */
282GLIB_AVAILABLE_IN_ALL
283void g_return_if_fail_warning (const char *log_domain,
284 const char *pretty_function,
285 const char *expression) G_ANALYZER_NORETURN;
286GLIB_AVAILABLE_IN_ALL
287void g_warn_message (const char *domain,
288 const char *file,
289 int line,
290 const char *func,
291 const char *warnexpr) G_ANALYZER_NORETURN;
292GLIB_DEPRECATED
293G_NORETURN
294void g_assert_warning (const char *log_domain,
295 const char *file,
296 const int line,
297 const char *pretty_function,
298 const char *expression);
299
300GLIB_AVAILABLE_IN_2_56
301void g_log_structured_standard (const gchar *log_domain,
302 GLogLevelFlags log_level,
303 const gchar *file,
304 const gchar *line,
305 const gchar *func,
306 const gchar *message_format,
307 ...) G_GNUC_PRINTF (6, 7);
308
309#ifndef G_LOG_DOMAIN
310#define G_LOG_DOMAIN ((gchar*) 0)
311#endif /* G_LOG_DOMAIN */
312
313#if defined(G_HAVE_ISO_VARARGS) && !G_ANALYZER_ANALYZING
314#if defined(G_LOG_USE_STRUCTURED) && GLIB_VERSION_MAX_ALLOWED >= GLIB_VERSION_2_56
315#define g_error(...) G_STMT_START { \
316 g_log_structured_standard (G_LOG_DOMAIN, G_LOG_LEVEL_ERROR, \
317 __FILE__, G_STRINGIFY (__LINE__), \
318 G_STRFUNC, __VA_ARGS__); \
319 for (;;) ; \
320 } G_STMT_END
321#define g_message(...) g_log_structured_standard (G_LOG_DOMAIN, G_LOG_LEVEL_MESSAGE, \
322 __FILE__, G_STRINGIFY (__LINE__), \
323 G_STRFUNC, __VA_ARGS__)
324#define g_critical(...) g_log_structured_standard (G_LOG_DOMAIN, G_LOG_LEVEL_CRITICAL, \
325 __FILE__, G_STRINGIFY (__LINE__), \
326 G_STRFUNC, __VA_ARGS__)
327#define g_warning(...) g_log_structured_standard (G_LOG_DOMAIN, G_LOG_LEVEL_WARNING, \
328 __FILE__, G_STRINGIFY (__LINE__), \
329 G_STRFUNC, __VA_ARGS__)
330#define g_info(...) g_log_structured_standard (G_LOG_DOMAIN, G_LOG_LEVEL_INFO, \
331 __FILE__, G_STRINGIFY (__LINE__), \
332 G_STRFUNC, __VA_ARGS__)
333#define g_debug(...) g_log_structured_standard (G_LOG_DOMAIN, G_LOG_LEVEL_DEBUG, \
334 __FILE__, G_STRINGIFY (__LINE__), \
335 G_STRFUNC, __VA_ARGS__)
336#else
337/* for(;;) ; so that GCC knows that control doesn't go past g_error().
338 * Put space before ending semicolon to avoid C++ build warnings.
339 */
340#define g_error(...) G_STMT_START { \
341 g_log (G_LOG_DOMAIN, \
342 G_LOG_LEVEL_ERROR, \
343 __VA_ARGS__); \
344 for (;;) ; \
345 } G_STMT_END
346#define g_message(...) g_log (G_LOG_DOMAIN, \
347 G_LOG_LEVEL_MESSAGE, \
348 __VA_ARGS__)
349#define g_critical(...) g_log (G_LOG_DOMAIN, \
350 G_LOG_LEVEL_CRITICAL, \
351 __VA_ARGS__)
352#define g_warning(...) g_log (G_LOG_DOMAIN, \
353 G_LOG_LEVEL_WARNING, \
354 __VA_ARGS__)
355#define g_info(...) g_log (G_LOG_DOMAIN, \
356 G_LOG_LEVEL_INFO, \
357 __VA_ARGS__)
358#define g_debug(...) g_log (G_LOG_DOMAIN, \
359 G_LOG_LEVEL_DEBUG, \
360 __VA_ARGS__)
361#endif
362#elif defined(G_HAVE_GNUC_VARARGS) && !G_ANALYZER_ANALYZING
363#if defined(G_LOG_USE_STRUCTURED) && GLIB_VERSION_MAX_ALLOWED >= GLIB_VERSION_2_56
364#define g_error(format...) G_STMT_START { \
365 g_log_structured_standard (G_LOG_DOMAIN, G_LOG_LEVEL_ERROR, \
366 __FILE__, G_STRINGIFY (__LINE__), \
367 G_STRFUNC, format); \
368 for (;;) ; \
369 } G_STMT_END
370#define g_message(format...) g_log_structured_standard (G_LOG_DOMAIN, G_LOG_LEVEL_MESSAGE, \
371 __FILE__, G_STRINGIFY (__LINE__), \
372 G_STRFUNC, format)
373#define g_critical(format...) g_log_structured_standard (G_LOG_DOMAIN, G_LOG_LEVEL_CRITICAL, \
374 __FILE__, G_STRINGIFY (__LINE__), \
375 G_STRFUNC, format)
376#define g_warning(format...) g_log_structured_standard (G_LOG_DOMAIN, G_LOG_LEVEL_WARNING, \
377 __FILE__, G_STRINGIFY (__LINE__), \
378 G_STRFUNC, format)
379#define g_info(format...) g_log_structured_standard (G_LOG_DOMAIN, G_LOG_LEVEL_INFO, \
380 __FILE__, G_STRINGIFY (__LINE__), \
381 G_STRFUNC, format)
382#define g_debug(format...) g_log_structured_standard (G_LOG_DOMAIN, G_LOG_LEVEL_DEBUG, \
383 __FILE__, G_STRINGIFY (__LINE__), \
384 G_STRFUNC, format)
385#else
386#define g_error(format...) G_STMT_START { \
387 g_log (G_LOG_DOMAIN, \
388 G_LOG_LEVEL_ERROR, \
389 format); \
390 for (;;) ; \
391 } G_STMT_END
392
393#define g_message(format...) g_log (G_LOG_DOMAIN, \
394 G_LOG_LEVEL_MESSAGE, \
395 format)
396#define g_critical(format...) g_log (G_LOG_DOMAIN, \
397 G_LOG_LEVEL_CRITICAL, \
398 format)
399#define g_warning(format...) g_log (G_LOG_DOMAIN, \
400 G_LOG_LEVEL_WARNING, \
401 format)
402#define g_info(format...) g_log (G_LOG_DOMAIN, \
403 G_LOG_LEVEL_INFO, \
404 format)
405#define g_debug(format...) g_log (G_LOG_DOMAIN, \
406 G_LOG_LEVEL_DEBUG, \
407 format)
408#endif
409#else /* no varargs macros */
410static G_NORETURN void g_error (const gchar *format, ...) G_ANALYZER_NORETURN;
411static void g_critical (const gchar *format, ...) G_ANALYZER_NORETURN;
412
413static inline void
414g_error (const gchar *format,
415 ...)
416{
417 va_list args;
418 va_start (args, format);
419 g_logv (G_LOG_DOMAIN, G_LOG_LEVEL_ERROR, format, args);
420 va_end (args);
421
422 for(;;) ;
423}
424static inline void
425g_message (const gchar *format,
426 ...)
427{
428 va_list args;
429 va_start (args, format);
430 g_logv (G_LOG_DOMAIN, G_LOG_LEVEL_MESSAGE, format, args);
431 va_end (args);
432}
433static inline void
434g_critical (const gchar *format,
435 ...)
436{
437 va_list args;
438 va_start (args, format);
439 g_logv (G_LOG_DOMAIN, G_LOG_LEVEL_CRITICAL, format, args);
440 va_end (args);
441}
442static inline void
443g_warning (const gchar *format,
444 ...)
445{
446 va_list args;
447 va_start (args, format);
448 g_logv (G_LOG_DOMAIN, G_LOG_LEVEL_WARNING, format, args);
449 va_end (args);
450}
451static inline void
452g_info (const gchar *format,
453 ...)
454{
455 va_list args;
456 va_start (args, format);
457 g_logv (G_LOG_DOMAIN, G_LOG_LEVEL_INFO, format, args);
458 va_end (args);
459}
460static inline void
461g_debug (const gchar *format,
462 ...)
463{
464 va_list args;
465 va_start (args, format);
466 g_logv (G_LOG_DOMAIN, G_LOG_LEVEL_DEBUG, format, args);
467 va_end (args);
468}
469#endif /* !__GNUC__ */
470
471/**
472 * g_warning_once:
473 * @...: format string, followed by parameters to insert
474 * into the format string (as with printf())
475 *
476 * Logs a warning only once.
477 *
478 * g_warning_once() calls g_warning() with the passed message the first time
479 * the statement is executed; subsequent times it is a no-op.
480 *
481 * Note! On platforms where the compiler doesn't support variadic macros, the
482 * warning is printed each time instead of only once.
483 *
484 * Since: 2.64
485 */
486#if defined(G_HAVE_ISO_VARARGS) && !G_ANALYZER_ANALYZING
487#define g_warning_once(...) \
488 G_STMT_START { \
489 static int G_PASTE (_GWarningOnceBoolean, __LINE__) = 0; /* (atomic) */ \
490 if (g_atomic_int_compare_and_exchange (&G_PASTE (_GWarningOnceBoolean, __LINE__), \
491 0, 1)) \
492 g_warning (__VA_ARGS__); \
493 } G_STMT_END \
494 GLIB_AVAILABLE_MACRO_IN_2_64
495#elif defined(G_HAVE_GNUC_VARARGS) && !G_ANALYZER_ANALYZING
496#define g_warning_once(format...) \
497 G_STMT_START { \
498 static int G_PASTE (_GWarningOnceBoolean, __LINE__) = 0; /* (atomic) */ \
499 if (g_atomic_int_compare_and_exchange (&G_PASTE (_GWarningOnceBoolean, __LINE__), \
500 0, 1)) \
501 g_warning (format); \
502 } G_STMT_END \
503 GLIB_AVAILABLE_MACRO_IN_2_64
504#else
505#define g_warning_once g_warning
506#endif
507
508/**
509 * GPrintFunc:
510 * @string: the message to output
511 *
512 * Specifies the type of the print handler functions.
513 * These are called with the complete formatted string to output.
514 */
515typedef void (*GPrintFunc) (const gchar *string);
516GLIB_AVAILABLE_IN_ALL
517void g_print (const gchar *format,
518 ...) G_GNUC_PRINTF (1, 2);
519GLIB_AVAILABLE_IN_ALL
520GPrintFunc g_set_print_handler (GPrintFunc func);
521GLIB_AVAILABLE_IN_ALL
522void g_printerr (const gchar *format,
523 ...) G_GNUC_PRINTF (1, 2);
524GLIB_AVAILABLE_IN_ALL
525GPrintFunc g_set_printerr_handler (GPrintFunc func);
526
527/**
528 * g_warn_if_reached:
529 *
530 * Logs a warning.
531 *
532 * Since: 2.16
533 */
534#define g_warn_if_reached() \
535 do { \
536 g_warn_message (G_LOG_DOMAIN, __FILE__, __LINE__, G_STRFUNC, NULL); \
537 } while (0)
538
539/**
540 * g_warn_if_fail:
541 * @expr: the expression to check
542 *
543 * Logs a warning if the expression is not true.
544 *
545 * Since: 2.16
546 */
547#define g_warn_if_fail(expr) \
548 do { \
549 if G_LIKELY (expr) ; \
550 else g_warn_message (G_LOG_DOMAIN, __FILE__, __LINE__, G_STRFUNC, #expr); \
551 } while (0)
552
553#ifdef G_DISABLE_CHECKS
554
555/**
556 * g_return_if_fail:
557 * @expr: the expression to check
558 *
559 * Verifies that the expression @expr, usually representing a precondition,
560 * evaluates to %TRUE. If the function returns a value, use
561 * g_return_val_if_fail() instead.
562 *
563 * If @expr evaluates to %FALSE, the current function should be considered to
564 * have undefined behaviour (a programmer error). The only correct solution
565 * to such an error is to change the module that is calling the current
566 * function, so that it avoids this incorrect call.
567 *
568 * To make this undefined behaviour visible, if @expr evaluates to %FALSE,
569 * the result is usually that a critical message is logged and the current
570 * function returns.
571 *
572 * If `G_DISABLE_CHECKS` is defined then the check is not performed. You
573 * should therefore not depend on any side effects of @expr.
574 *
575 * To debug failure of a g_return_if_fail() check, run the code under a debugger
576 * with `G_DEBUG=fatal-criticals` or `G_DEBUG=fatal-warnings` defined in the
577 * environment (see [Running GLib Applications](glib-running.html)):
578 *
579 * |[
580 * G_DEBUG=fatal-warnings gdb ./my-program
581 * ]|
582 *
583 * Any unrelated failures can be skipped over in
584 * [gdb](https://www.gnu.org/software/gdb/) using the `continue` command.
585 */
586#define g_return_if_fail(expr) G_STMT_START{ (void)0; }G_STMT_END
587
588/**
589 * g_return_val_if_fail:
590 * @expr: the expression to check
591 * @val: the value to return from the current function
592 * if the expression is not true
593 *
594 * Verifies that the expression @expr, usually representing a precondition,
595 * evaluates to %TRUE. If the function does not return a value, use
596 * g_return_if_fail() instead.
597 *
598 * If @expr evaluates to %FALSE, the current function should be considered to
599 * have undefined behaviour (a programmer error). The only correct solution
600 * to such an error is to change the module that is calling the current
601 * function, so that it avoids this incorrect call.
602 *
603 * To make this undefined behaviour visible, if @expr evaluates to %FALSE,
604 * the result is usually that a critical message is logged and @val is
605 * returned from the current function.
606 *
607 * If `G_DISABLE_CHECKS` is defined then the check is not performed. You
608 * should therefore not depend on any side effects of @expr.
609 *
610 * See g_return_if_fail() for guidance on how to debug failure of this check.
611 */
612#define g_return_val_if_fail(expr,val) G_STMT_START{ (void)0; }G_STMT_END
613
614/**
615 * g_return_if_reached:
616 *
617 * Logs a critical message and returns from the current function.
618 * This can only be used in functions which do not return a value.
619 *
620 * See g_return_if_fail() for guidance on how to debug failure of this check.
621 */
622#define g_return_if_reached() G_STMT_START{ return; }G_STMT_END
623
624/**
625 * g_return_val_if_reached:
626 * @val: the value to return from the current function
627 *
628 * Logs a critical message and returns @val.
629 *
630 * See g_return_if_fail() for guidance on how to debug failure of this check.
631 */
632#define g_return_val_if_reached(val) G_STMT_START{ return (val); }G_STMT_END
633
634#else /* !G_DISABLE_CHECKS */
635
636#define g_return_if_fail(expr) \
637 G_STMT_START { \
638 if (G_LIKELY (expr)) \
639 { } \
640 else \
641 { \
642 g_return_if_fail_warning (G_LOG_DOMAIN, \
643 G_STRFUNC, \
644 #expr); \
645 return; \
646 } \
647 } G_STMT_END
648
649#define g_return_val_if_fail(expr, val) \
650 G_STMT_START { \
651 if (G_LIKELY (expr)) \
652 { } \
653 else \
654 { \
655 g_return_if_fail_warning (G_LOG_DOMAIN, \
656 G_STRFUNC, \
657 #expr); \
658 return (val); \
659 } \
660 } G_STMT_END
661
662#define g_return_if_reached() \
663 G_STMT_START { \
664 g_log (G_LOG_DOMAIN, \
665 G_LOG_LEVEL_CRITICAL, \
666 "file %s: line %d (%s): should not be reached", \
667 __FILE__, \
668 __LINE__, \
669 G_STRFUNC); \
670 return; \
671 } G_STMT_END
672
673#define g_return_val_if_reached(val) \
674 G_STMT_START { \
675 g_log (G_LOG_DOMAIN, \
676 G_LOG_LEVEL_CRITICAL, \
677 "file %s: line %d (%s): should not be reached", \
678 __FILE__, \
679 __LINE__, \
680 G_STRFUNC); \
681 return (val); \
682 } G_STMT_END
683
684#endif /* !G_DISABLE_CHECKS */
685
686G_END_DECLS
687
688#endif /* __G_MESSAGES_H__ */
689

source code of include/glib-2.0/glib/gmessages.h