gmacros.h: offsetof is also available on MSVC
[glib.git] / glib / gmacros.h
blob75834795a4952ec7d35fcfe959da577b9f2e68f2
1 /* GLIB - Library of useful routines for C programming
2 * Copyright (C) 1995-1997 Peter Mattis, Spencer Kimball and Josh MacDonald
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 of the License, or (at your option) any later version.
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.
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/>.
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/.
25 /* This file must not include any other glib header file and must thus
26 * not refer to variables from glibconfig.h
29 #ifndef __G_MACROS_H__
30 #define __G_MACROS_H__
32 #if !defined (__GLIB_H_INSIDE__) && !defined (GLIB_COMPILATION)
33 #error "Only <glib.h> can be included directly."
34 #endif
36 /* We include stddef.h to get the system's definition of NULL
38 #include <stddef.h>
40 #define G_GNUC_CHECK_VERSION(major, minor) \
41 (defined(__GNUC__) && \
42 ((__GNUC__ > (major)) || \
43 ((__GNUC__ == (major)) && \
44 (__GNUC_MINOR__ >= (minor)))))
46 /* Here we provide G_GNUC_EXTENSION as an alias for __extension__,
47 * where this is valid. This allows for warningless compilation of
48 * "long long" types even in the presence of '-ansi -pedantic'.
50 #if __GNUC__ > 2 || (__GNUC__ == 2 && __GNUC_MINOR__ >= 8)
51 #define G_GNUC_EXTENSION __extension__
52 #else
53 #define G_GNUC_EXTENSION
54 #endif
56 /* Every compiler that we target supports inlining, but some of them may
57 * complain about it if we don't say "__inline". If we have C99, or if
58 * we are using C++, then we can use "inline" directly. Unfortunately
59 * Visual Studio does not support __STDC_VERSION__, so we need to check
60 * whether we are on Visual Studio 2013 or earlier to see that we need to
61 * say "__inline" in C mode.
62 * Otherwise, we say "__inline" to avoid the warning.
64 #define G_CAN_INLINE
65 #ifndef __cplusplus
66 # ifdef _MSC_VER
67 # if (_MSC_VER < 1900)
68 # define G_INLINE_DEFINE_NEEDED
69 # endif
70 # elif !defined(__STDC_VERSION__) || (__STDC_VERSION__ < 199900)
71 # define G_INLINE_DEFINE_NEEDED
72 # endif
73 #endif
75 #ifdef G_INLINE_DEFINE_NEEDED
76 # undef inline
77 # define inline __inline
78 #endif
80 #undef G_INLINE_DEFINE_NEEDED
82 /* For historical reasons we need to continue to support those who
83 * define G_IMPLEMENT_INLINES to mean "don't implement this here".
85 #ifdef G_IMPLEMENT_INLINES
86 # define G_INLINE_FUNC extern
87 # undef G_CAN_INLINE
88 #else
89 # define G_INLINE_FUNC static inline
90 #endif /* G_IMPLEMENT_INLINES */
92 /* Provide macros to feature the GCC function attribute.
94 #if __GNUC__ > 2 || (__GNUC__ == 2 && __GNUC_MINOR__ >= 96)
95 #define G_GNUC_PURE __attribute__((__pure__))
96 #define G_GNUC_MALLOC __attribute__((__malloc__))
97 #else
98 #define G_GNUC_PURE
99 #define G_GNUC_MALLOC
100 #endif
102 #if __GNUC__ >= 4
103 #define G_GNUC_NULL_TERMINATED __attribute__((__sentinel__))
104 #else
105 #define G_GNUC_NULL_TERMINATED
106 #endif
108 /* Clang feature detection: http://clang.llvm.org/docs/LanguageExtensions.html */
109 #ifndef __has_attribute
110 #define __has_attribute(x) 0
111 #endif
113 #ifndef __has_feature
114 #define __has_feature(x) 0
115 #endif
117 #ifndef __has_builtin
118 #define __has_builtin(x) 0
119 #endif
121 #if (!defined(__clang__) && ((__GNUC__ > 4) || (__GNUC__ == 4 && __GNUC_MINOR__ >= 3))) || \
122 (defined(__clang__) && __has_attribute(__alloc_size__))
123 #define G_GNUC_ALLOC_SIZE(x) __attribute__((__alloc_size__(x)))
124 #define G_GNUC_ALLOC_SIZE2(x,y) __attribute__((__alloc_size__(x,y)))
125 #else
126 #define G_GNUC_ALLOC_SIZE(x)
127 #define G_GNUC_ALLOC_SIZE2(x,y)
128 #endif
130 #if __GNUC__ > 2 || (__GNUC__ == 2 && __GNUC_MINOR__ > 4)
131 #define G_GNUC_PRINTF( format_idx, arg_idx ) \
132 __attribute__((__format__ (__printf__, format_idx, arg_idx)))
133 #define G_GNUC_SCANF( format_idx, arg_idx ) \
134 __attribute__((__format__ (__scanf__, format_idx, arg_idx)))
135 #define G_GNUC_FORMAT( arg_idx ) \
136 __attribute__((__format_arg__ (arg_idx)))
137 #define G_GNUC_NORETURN \
138 __attribute__((__noreturn__))
139 #define G_GNUC_CONST \
140 __attribute__((__const__))
141 #define G_GNUC_UNUSED \
142 __attribute__((__unused__))
143 #define G_GNUC_NO_INSTRUMENT \
144 __attribute__((__no_instrument_function__))
145 #else /* !__GNUC__ */
146 #define G_GNUC_PRINTF( format_idx, arg_idx )
147 #define G_GNUC_SCANF( format_idx, arg_idx )
148 #define G_GNUC_FORMAT( arg_idx )
149 #define G_GNUC_NORETURN
150 #define G_GNUC_CONST
151 #define G_GNUC_UNUSED
152 #define G_GNUC_NO_INSTRUMENT
153 #endif /* !__GNUC__ */
155 #if __GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 1)
156 #define G_GNUC_DEPRECATED __attribute__((__deprecated__))
157 #else
158 #define G_GNUC_DEPRECATED
159 #endif /* __GNUC__ */
161 #if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 5)
162 #define G_GNUC_DEPRECATED_FOR(f) \
163 __attribute__((deprecated("Use " #f " instead")))
164 #else
165 #define G_GNUC_DEPRECATED_FOR(f) G_GNUC_DEPRECATED
166 #endif /* __GNUC__ */
168 #if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 6)
169 #define G_GNUC_BEGIN_IGNORE_DEPRECATIONS \
170 _Pragma ("GCC diagnostic push") \
171 _Pragma ("GCC diagnostic ignored \"-Wdeprecated-declarations\"")
172 #define G_GNUC_END_IGNORE_DEPRECATIONS \
173 _Pragma ("GCC diagnostic pop")
174 #elif defined (_MSC_VER) && (_MSC_VER >= 1500)
175 #define G_GNUC_BEGIN_IGNORE_DEPRECATIONS \
176 __pragma (warning (push)) \
177 __pragma (warning (disable : 4996))
178 #define G_GNUC_END_IGNORE_DEPRECATIONS \
179 __pragma (warning (pop))
180 #elif defined (__clang__)
181 #define G_GNUC_BEGIN_IGNORE_DEPRECATIONS \
182 _Pragma("clang diagnostic push") \
183 _Pragma("clang diagnostic ignored \"-Wdeprecated-declarations\"")
184 #define G_GNUC_END_IGNORE_DEPRECATIONS \
185 _Pragma("clang diagnostic pop")
186 #else
187 #define G_GNUC_BEGIN_IGNORE_DEPRECATIONS
188 #define G_GNUC_END_IGNORE_DEPRECATIONS
189 #endif
191 #if __GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 3)
192 #define G_GNUC_MAY_ALIAS __attribute__((may_alias))
193 #else
194 #define G_GNUC_MAY_ALIAS
195 #endif
197 #if __GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 4)
198 #define G_GNUC_WARN_UNUSED_RESULT __attribute__((warn_unused_result))
199 #else
200 #define G_GNUC_WARN_UNUSED_RESULT
201 #endif /* __GNUC__ */
203 #ifndef G_DISABLE_DEPRECATED
204 /* Wrap the gcc __PRETTY_FUNCTION__ and __FUNCTION__ variables with
205 * macros, so we can refer to them as strings unconditionally.
206 * usage not-recommended since gcc-3.0
208 #if defined (__GNUC__) && (__GNUC__ < 3)
209 #define G_GNUC_FUNCTION __FUNCTION__
210 #define G_GNUC_PRETTY_FUNCTION __PRETTY_FUNCTION__
211 #else /* !__GNUC__ */
212 #define G_GNUC_FUNCTION ""
213 #define G_GNUC_PRETTY_FUNCTION ""
214 #endif /* !__GNUC__ */
215 #endif /* !G_DISABLE_DEPRECATED */
217 #if __has_feature(attribute_analyzer_noreturn) && defined(__clang_analyzer__)
218 #define G_ANALYZER_ANALYZING 1
219 #define G_ANALYZER_NORETURN __attribute__((analyzer_noreturn))
220 #else
221 #define G_ANALYZER_ANALYZING 0
222 #define G_ANALYZER_NORETURN
223 #endif
225 #define G_STRINGIFY(macro_or_string) G_STRINGIFY_ARG (macro_or_string)
226 #define G_STRINGIFY_ARG(contents) #contents
228 #ifndef __GI_SCANNER__ /* The static assert macro really confuses the introspection parser */
229 #define G_PASTE_ARGS(identifier1,identifier2) identifier1 ## identifier2
230 #define G_PASTE(identifier1,identifier2) G_PASTE_ARGS (identifier1, identifier2)
231 #ifdef __COUNTER__
232 #define G_STATIC_ASSERT(expr) typedef char G_PASTE (_GStaticAssertCompileTimeAssertion_, __COUNTER__)[(expr) ? 1 : -1] G_GNUC_UNUSED
233 #else
234 #define G_STATIC_ASSERT(expr) typedef char G_PASTE (_GStaticAssertCompileTimeAssertion_, __LINE__)[(expr) ? 1 : -1] G_GNUC_UNUSED
235 #endif
236 #define G_STATIC_ASSERT_EXPR(expr) ((void) sizeof (char[(expr) ? 1 : -1]))
237 #endif
239 /* Provide a string identifying the current code position */
240 #if defined(__GNUC__) && (__GNUC__ < 3) && !defined(__cplusplus)
241 #define G_STRLOC __FILE__ ":" G_STRINGIFY (__LINE__) ":" __PRETTY_FUNCTION__ "()"
242 #else
243 #define G_STRLOC __FILE__ ":" G_STRINGIFY (__LINE__)
244 #endif
246 /* Provide a string identifying the current function, non-concatenatable */
247 #if defined (__GNUC__) && defined (__cplusplus)
248 #define G_STRFUNC ((const char*) (__PRETTY_FUNCTION__))
249 #elif defined (__STDC_VERSION__) && __STDC_VERSION__ >= 199901L
250 #define G_STRFUNC ((const char*) (__func__))
251 #elif defined (__GNUC__) || (defined(_MSC_VER) && (_MSC_VER > 1300))
252 #define G_STRFUNC ((const char*) (__FUNCTION__))
253 #else
254 #define G_STRFUNC ((const char*) ("???"))
255 #endif
257 /* Guard C code in headers, while including them from C++ */
258 #ifdef __cplusplus
259 #define G_BEGIN_DECLS extern "C" {
260 #define G_END_DECLS }
261 #else
262 #define G_BEGIN_DECLS
263 #define G_END_DECLS
264 #endif
266 /* Provide definitions for some commonly used macros.
267 * Some of them are only provided if they haven't already
268 * been defined. It is assumed that if they are already
269 * defined then the current definition is correct.
271 #ifndef NULL
272 # ifdef __cplusplus
273 # define NULL (0L)
274 # else /* !__cplusplus */
275 # define NULL ((void*) 0)
276 # endif /* !__cplusplus */
277 #endif
279 #ifndef FALSE
280 #define FALSE (0)
281 #endif
283 #ifndef TRUE
284 #define TRUE (!FALSE)
285 #endif
287 #undef MAX
288 #define MAX(a, b) (((a) > (b)) ? (a) : (b))
290 #undef MIN
291 #define MIN(a, b) (((a) < (b)) ? (a) : (b))
293 #undef ABS
294 #define ABS(a) (((a) < 0) ? -(a) : (a))
296 #undef CLAMP
297 #define CLAMP(x, low, high) (((x) > (high)) ? (high) : (((x) < (low)) ? (low) : (x)))
299 /* Count the number of elements in an array. The array must be defined
300 * as such; using this with a dynamically allocated array will give
301 * incorrect results.
303 #define G_N_ELEMENTS(arr) (sizeof (arr) / sizeof ((arr)[0]))
305 /* Macros by analogy to GINT_TO_POINTER, GPOINTER_TO_INT
307 #define GPOINTER_TO_SIZE(p) ((gsize) (p))
308 #define GSIZE_TO_POINTER(s) ((gpointer) (gsize) (s))
310 /* Provide convenience macros for handling structure
311 * fields through their offsets.
314 #if (defined(__GNUC__) && __GNUC__ >= 4) || defined (_MSC_VER)
315 #define G_STRUCT_OFFSET(struct_type, member) \
316 ((glong) offsetof (struct_type, member))
317 #else
318 #define G_STRUCT_OFFSET(struct_type, member) \
319 ((glong) ((guint8*) &((struct_type*) 0)->member))
320 #endif
322 #define G_STRUCT_MEMBER_P(struct_p, struct_offset) \
323 ((gpointer) ((guint8*) (struct_p) + (glong) (struct_offset)))
324 #define G_STRUCT_MEMBER(member_type, struct_p, struct_offset) \
325 (*(member_type*) G_STRUCT_MEMBER_P ((struct_p), (struct_offset)))
327 /* Provide simple macro statement wrappers:
328 * G_STMT_START { statements; } G_STMT_END;
329 * This can be used as a single statement, like:
330 * if (x) G_STMT_START { ... } G_STMT_END; else ...
331 * This intentionally does not use compiler extensions like GCC's '({...})' to
332 * avoid portability issue or side effects when compiled with different compilers.
333 * MSVC complains about "while(0)": C4127: "Conditional expression is constant",
334 * so we use __pragma to avoid the warning since the use here is intentional.
336 #if !(defined (G_STMT_START) && defined (G_STMT_END))
337 #define G_STMT_START do
338 #if defined (_MSC_VER) && (_MSC_VER >= 1500)
339 #define G_STMT_END \
340 __pragma(warning(push)) \
341 __pragma(warning(disable:4127)) \
342 while(0) \
343 __pragma(warning(pop))
344 #else
345 #define G_STMT_END while (0)
346 #endif
347 #endif
349 /* Deprecated -- do not use. */
350 #ifndef G_DISABLE_DEPRECATED
351 #ifdef G_DISABLE_CONST_RETURNS
352 #define G_CONST_RETURN
353 #else
354 #define G_CONST_RETURN const
355 #endif
356 #endif
359 * The G_LIKELY and G_UNLIKELY macros let the programmer give hints to
360 * the compiler about the expected result of an expression. Some compilers
361 * can use this information for optimizations.
363 * The _G_BOOLEAN_EXPR macro is intended to trigger a gcc warning when
364 * putting assignments in g_return_if_fail ().
366 #if defined(__GNUC__) && (__GNUC__ > 2) && defined(__OPTIMIZE__)
367 #define _G_BOOLEAN_EXPR(expr) \
368 G_GNUC_EXTENSION ({ \
369 int _g_boolean_var_; \
370 if (expr) \
371 _g_boolean_var_ = 1; \
372 else \
373 _g_boolean_var_ = 0; \
374 _g_boolean_var_; \
376 #define G_LIKELY(expr) (__builtin_expect (_G_BOOLEAN_EXPR((expr)), 1))
377 #define G_UNLIKELY(expr) (__builtin_expect (_G_BOOLEAN_EXPR((expr)), 0))
378 #else
379 #define G_LIKELY(expr) (expr)
380 #define G_UNLIKELY(expr) (expr)
381 #endif
383 #if __GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 1)
384 #define G_DEPRECATED __attribute__((__deprecated__))
385 #elif defined(_MSC_VER) && (_MSC_VER >= 1300)
386 #define G_DEPRECATED __declspec(deprecated)
387 #else
388 #define G_DEPRECATED
389 #endif
391 #if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 5)
392 #define G_DEPRECATED_FOR(f) __attribute__((__deprecated__("Use '" #f "' instead")))
393 #elif defined(_MSC_FULL_VER) && (_MSC_FULL_VER > 140050320)
394 #define G_DEPRECATED_FOR(f) __declspec(deprecated("is deprecated. Use '" #f "' instead"))
395 #else
396 #define G_DEPRECATED_FOR(f) G_DEPRECATED
397 #endif
399 #if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 5)
400 #define G_UNAVAILABLE(maj,min) __attribute__((deprecated("Not available before " #maj "." #min)))
401 #elif defined(_MSC_FULL_VER) && (_MSC_FULL_VER > 140050320)
402 #define G_UNAVAILABLE(maj,min) __declspec(deprecated("is not available before " #maj "." #min))
403 #else
404 #define G_UNAVAILABLE(maj,min) G_DEPRECATED
405 #endif
407 #ifndef _GLIB_EXTERN
408 #define _GLIB_EXTERN extern
409 #endif
411 /* These macros are used to mark deprecated functions in GLib headers,
412 * and thus have to be exposed in installed headers. But please
413 * do *not* use them in other projects. Instead, use G_DEPRECATED
414 * or define your own wrappers around it.
417 #ifdef GLIB_DISABLE_DEPRECATION_WARNINGS
418 #define GLIB_DEPRECATED _GLIB_EXTERN
419 #define GLIB_DEPRECATED_FOR(f) _GLIB_EXTERN
420 #define GLIB_UNAVAILABLE(maj,min) _GLIB_EXTERN
421 #else
422 #define GLIB_DEPRECATED G_DEPRECATED _GLIB_EXTERN
423 #define GLIB_DEPRECATED_FOR(f) G_DEPRECATED_FOR(f) _GLIB_EXTERN
424 #define GLIB_UNAVAILABLE(maj,min) G_UNAVAILABLE(maj,min) _GLIB_EXTERN
425 #endif
427 #ifdef __GNUC__
429 /* these macros are private */
430 #define _GLIB_AUTOPTR_FUNC_NAME(TypeName) glib_autoptr_cleanup_##TypeName
431 #define _GLIB_AUTOPTR_TYPENAME(TypeName) TypeName##_autoptr
432 #define _GLIB_AUTO_FUNC_NAME(TypeName) glib_auto_cleanup_##TypeName
433 #define _GLIB_CLEANUP(func) __attribute__((cleanup(func)))
434 #define _GLIB_DEFINE_AUTOPTR_CHAINUP(ModuleObjName, ParentName) \
435 typedef ModuleObjName *_GLIB_AUTOPTR_TYPENAME(ModuleObjName); \
436 static inline void _GLIB_AUTOPTR_FUNC_NAME(ModuleObjName) (ModuleObjName **_ptr) { \
437 _GLIB_AUTOPTR_FUNC_NAME(ParentName) ((ParentName **) _ptr); } \
440 /* these macros are API */
441 #define G_DEFINE_AUTOPTR_CLEANUP_FUNC(TypeName, func) \
442 typedef TypeName *_GLIB_AUTOPTR_TYPENAME(TypeName); \
443 G_GNUC_BEGIN_IGNORE_DEPRECATIONS \
444 static inline void _GLIB_AUTOPTR_FUNC_NAME(TypeName) (TypeName **_ptr) { if (*_ptr) (func) (*_ptr); } \
445 G_GNUC_END_IGNORE_DEPRECATIONS
446 #define G_DEFINE_AUTO_CLEANUP_CLEAR_FUNC(TypeName, func) \
447 G_GNUC_BEGIN_IGNORE_DEPRECATIONS \
448 static inline void _GLIB_AUTO_FUNC_NAME(TypeName) (TypeName *_ptr) { (func) (_ptr); } \
449 G_GNUC_END_IGNORE_DEPRECATIONS
450 #define G_DEFINE_AUTO_CLEANUP_FREE_FUNC(TypeName, func, none) \
451 G_GNUC_BEGIN_IGNORE_DEPRECATIONS \
452 static inline void _GLIB_AUTO_FUNC_NAME(TypeName) (TypeName *_ptr) { if (*_ptr != none) (func) (*_ptr); } \
453 G_GNUC_END_IGNORE_DEPRECATIONS
454 #define g_autoptr(TypeName) _GLIB_CLEANUP(_GLIB_AUTOPTR_FUNC_NAME(TypeName)) _GLIB_AUTOPTR_TYPENAME(TypeName)
455 #define g_auto(TypeName) _GLIB_CLEANUP(_GLIB_AUTO_FUNC_NAME(TypeName)) TypeName
456 #define g_autofree _GLIB_CLEANUP(g_autoptr_cleanup_generic_gfree)
458 #else /* not GNU C */
459 /* this (dummy) macro is private */
460 #define _GLIB_DEFINE_AUTOPTR_CHAINUP(ModuleObjName, ParentName)
462 /* these (dummy) macros are API */
463 #define G_DEFINE_AUTOPTR_CLEANUP_FUNC(TypeName, func)
464 #define G_DEFINE_AUTO_CLEANUP_CLEAR_FUNC(TypeName, func)
465 #define G_DEFINE_AUTO_CLEANUP_FREE_FUNC(TypeName, func, none)
467 /* no declaration of g_auto() or g_autoptr() here */
468 #endif
470 #endif /* __G_MACROS_H__ */