-
Notifications
You must be signed in to change notification settings - Fork 0
/
Copy pathgnulib-common.m4
1767 lines (1676 loc) · 68 KB
/
gnulib-common.m4
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
# gnulib-common.m4
# serial 107
dnl Copyright (C) 2007-2025 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
dnl with or without modifications, as long as this notice is preserved.
dnl This file is offered as-is, without any warranty.
AC_PREREQ([2.62])
# gl_COMMON
# is expanded unconditionally through gnulib-tool magic.
AC_DEFUN([gl_COMMON], [
dnl Use AC_REQUIRE here, so that the code is expanded once only.
AC_REQUIRE([gl_00GNULIB])
AC_REQUIRE([gl_COMMON_BODY])
AC_REQUIRE([gl_ZZGNULIB])
])
AC_DEFUN([gl_COMMON_BODY], [
AH_VERBATIM([0witness],
[/* Witness that <config.h> has been included. */
#define _GL_CONFIG_H_INCLUDED 1
])
AH_VERBATIM([_GL_GNUC_PREREQ],
[/* True if the compiler says it groks GNU C version MAJOR.MINOR.
Except that
- clang groks GNU C 4.2, even on Windows, where it does not define
__GNUC__.
- The OpenMandriva-modified clang compiler pretends that it groks
GNU C version 13.1, but it doesn't: It does not support
__attribute__ ((__malloc__ (f, i))), nor does it support
__attribute__ ((__warning__ (message))) on a function redeclaration.
- Users can make clang lie as well, through the -fgnuc-version option. */
#if defined __GNUC__ && defined __GNUC_MINOR__ && !defined __clang__
# define _GL_GNUC_PREREQ(major, minor) \
((major) < __GNUC__ + ((minor) <= __GNUC_MINOR__))
#elif defined __clang__
/* clang really only groks GNU C 4.2. */
# define _GL_GNUC_PREREQ(major, minor) \
((major) < 4 + ((minor) <= 2))
#else
# define _GL_GNUC_PREREQ(major, minor) 0
#endif
])
AH_VERBATIM([_Noreturn],
[/* The _Noreturn keyword of C11. */
#ifndef _Noreturn
# if (defined __cplusplus \
&& ((201103 <= __cplusplus && !(__GNUC__ == 4 && __GNUC_MINOR__ == 7)) \
|| (defined _MSC_VER && 1900 <= _MSC_VER)) \
&& 0)
/* [[noreturn]] is not practically usable, because with it the syntax
extern _Noreturn void func (...);
would not be valid; such a declaration would only be valid with 'extern'
and '_Noreturn' swapped, or without the 'extern' keyword. However, some
AIX system header files and several gnulib header files use precisely
this syntax with 'extern'. */
# define _Noreturn [[noreturn]]
# elif (defined __clang__ && __clang_major__ < 16 \
&& defined _GL_WORK_AROUND_LLVM_BUG_59792)
/* Compile with -D_GL_WORK_AROUND_LLVM_BUG_59792 to work around
that rare LLVM bug, though you may get many false-alarm warnings. */
# define _Noreturn
# elif ((!defined __cplusplus || defined __clang__) \
&& (201112 <= (defined __STDC_VERSION__ ? __STDC_VERSION__ : 0) \
|| (!defined __STRICT_ANSI__ \
&& (_GL_GNUC_PREREQ (4, 7) \
|| (defined __apple_build_version__ \
? 6000000 <= __apple_build_version__ \
: 3 < __clang_major__ + (5 <= __clang_minor__))))))
/* _Noreturn works as-is. */
# elif _GL_GNUC_PREREQ (2, 8) || defined __clang__ || 0x5110 <= __SUNPRO_C
# define _Noreturn __attribute__ ((__noreturn__))
# elif 1200 <= (defined _MSC_VER ? _MSC_VER : 0)
# define _Noreturn __declspec (noreturn)
# else
# define _Noreturn
# endif
#endif
])
AH_VERBATIM([isoc99_inline],
[/* Work around a bug in Apple GCC 4.0.1 build 5465: In C99 mode, it supports
the ISO C 99 semantics of 'extern inline' (unlike the GNU C semantics of
earlier versions), but does not display it by setting __GNUC_STDC_INLINE__.
__APPLE__ && __MACH__ test for Mac OS X.
__APPLE_CC__ tests for the Apple compiler and its version.
__STDC_VERSION__ tests for the C99 mode. */
#if defined __APPLE__ && defined __MACH__ && __APPLE_CC__ >= 5465 && !defined __cplusplus && __STDC_VERSION__ >= 199901L && !defined __GNUC_STDC_INLINE__
# define __GNUC_STDC_INLINE__ 1
#endif])
AH_VERBATIM([attribute],
[/* Attributes. */
/* Define _GL_HAS_ATTRIBUTE only once, because on FreeBSD, with gcc < 5, if
<config.h> gets included once again after <sys/cdefs.h>, __has_attribute(x)
expands to 0 always, and redefining _GL_HAS_ATTRIBUTE would turn off all
attributes. */
#ifndef _GL_HAS_ATTRIBUTE
# if (defined __has_attribute \
&& (!defined __clang_minor__ \
|| (defined __apple_build_version__ \
? 7000000 <= __apple_build_version__ \
: 5 <= __clang_major__)))
# define _GL_HAS_ATTRIBUTE(attr) __has_attribute (__##attr##__)
# else
# define _GL_HAS_ATTRIBUTE(attr) _GL_ATTR_##attr
# define _GL_ATTR_alloc_size _GL_GNUC_PREREQ (4, 3)
# define _GL_ATTR_always_inline _GL_GNUC_PREREQ (3, 2)
# define _GL_ATTR_artificial _GL_GNUC_PREREQ (4, 3)
# define _GL_ATTR_cold _GL_GNUC_PREREQ (4, 3)
# define _GL_ATTR_const _GL_GNUC_PREREQ (2, 95)
# define _GL_ATTR_deprecated _GL_GNUC_PREREQ (3, 1)
# define _GL_ATTR_diagnose_if 0
# define _GL_ATTR_error _GL_GNUC_PREREQ (4, 3)
# define _GL_ATTR_externally_visible _GL_GNUC_PREREQ (4, 1)
# define _GL_ATTR_fallthrough _GL_GNUC_PREREQ (7, 0)
# define _GL_ATTR_format _GL_GNUC_PREREQ (2, 7)
# define _GL_ATTR_leaf _GL_GNUC_PREREQ (4, 6)
# define _GL_ATTR_malloc _GL_GNUC_PREREQ (3, 0)
# ifdef _ICC
# define _GL_ATTR_may_alias 0
# else
# define _GL_ATTR_may_alias _GL_GNUC_PREREQ (3, 3)
# endif
# define _GL_ATTR_noinline _GL_GNUC_PREREQ (3, 1)
# define _GL_ATTR_nonnull _GL_GNUC_PREREQ (3, 3)
# define _GL_ATTR_nonstring _GL_GNUC_PREREQ (8, 0)
# define _GL_ATTR_nothrow _GL_GNUC_PREREQ (3, 3)
# define _GL_ATTR_packed _GL_GNUC_PREREQ (2, 7)
# define _GL_ATTR_pure _GL_GNUC_PREREQ (2, 96)
# define _GL_ATTR_reproducible 0 /* not yet supported, as of GCC 14 */
# define _GL_ATTR_returns_nonnull _GL_GNUC_PREREQ (4, 9)
# define _GL_ATTR_sentinel _GL_GNUC_PREREQ (4, 0)
# define _GL_ATTR_unsequenced 0 /* not yet supported, as of GCC 14 */
# define _GL_ATTR_unused _GL_GNUC_PREREQ (2, 7)
# define _GL_ATTR_warn_unused_result _GL_GNUC_PREREQ (3, 4)
# endif
#endif
/* Use __has_c_attribute if available. However, do not use with
pre-C23 GCC, which can issue false positives if -Wpedantic. */
#if (defined __has_c_attribute \
&& ! (_GL_GNUC_PREREQ (4, 6) \
&& (defined __STDC_VERSION__ ? __STDC_VERSION__ : 0) <= 201710))
# define _GL_HAVE___HAS_C_ATTRIBUTE 1
#else
# define _GL_HAVE___HAS_C_ATTRIBUTE 0
#endif
/* Attributes in bracket syntax [[...]] vs. attributes in __attribute__((...))
syntax, in function declarations. There are two problems here.
(Last tested with gcc/g++ 14 and clang/clang++ 18.)
1) We want that the _GL_ATTRIBUTE_* can be cumulated on the same declaration
in any order.
=========================== foo.c = foo.cc ===========================
__attribute__ ((__deprecated__)) [[__nodiscard__]] int bar1 (int);
[[__nodiscard__]] __attribute__ ((__deprecated__)) int bar2 (int);
======================================================================
This gives a syntax error
- in C mode with gcc
<https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108796>, and
- in C++ mode with clang++ version < 16, and
- in C++ mode, inside extern "C" {}, still in newer clang++ versions
<https://github.com/llvm/llvm-project/issues/101990>.
*/
/* Define if, in a function declaration, the attributes in bracket syntax
[[...]] must come before the attributes in __attribute__((...)) syntax.
If this is defined, it is best to avoid the bracket syntax, so that the
various _GL_ATTRIBUTE_* can be cumulated on the same declaration in any
order. */
#ifdef __cplusplus
# if defined __clang__
# define _GL_BRACKET_BEFORE_ATTRIBUTE 1
# endif
#else
# if defined __GNUC__ && !defined __clang__
# define _GL_BRACKET_BEFORE_ATTRIBUTE 1
# endif
#endif
/*
2) We want that the _GL_ATTRIBUTE_* can be placed in a declaration
- without 'extern', in C as well as in C++,
- with 'extern', in C,
- with 'extern "C"', in C++
in the same position. That is, we don't want to be forced to use a
macro which arranges for the attribute to come before 'extern' in
one case and after 'extern' in the other case, because such a macro
would make the source code of .h files pretty ugly.
=========================== foo.c = foo.cc ===========================
#ifdef __cplusplus
# define CC "C"
#else
# define CC
#endif
#define ND [[__nodiscard__]]
#define WUR __attribute__((__warn_unused_result__))
#ifdef __cplusplus
extern "C" {
#endif
// gcc clang g++ clang++
ND int foo (int);
int ND foo (int); // warn error warn error
int foo ND (int);
int foo (int) ND; // warn error warn error
WUR int foo (int);
int WUR foo (int);
int fo1 WUR (int); // error error error error
int foo (int) WUR;
#ifdef __cplusplus
}
#endif
// gcc clang g++ clang++
ND extern CC int foo (int); // error error
extern CC ND int foo (int); // error error
extern CC int ND foo (int); // warn error warn error
extern CC int foo ND (int);
extern CC int foo (int) ND; // warn error warn error
WUR extern CC int foo (int); // warn
extern CC WUR int foo (int);
extern CC int WUR foo (int);
extern CC int foo WUR (int); // error error error error
extern CC int foo (int) WUR;
ND EXTERN_C_FUNC int foo (int); // error error
EXTERN_C_FUNC ND int foo (int);
EXTERN_C_FUNC int ND foo (int); // warn error warn error
EXTERN_C_FUNC int foo ND (int);
EXTERN_C_FUNC int foo (int) ND; // warn error warn error
WUR EXTERN_C_FUNC int foo (int); // warn
EXTERN_C_FUNC WUR int foo (int);
EXTERN_C_FUNC int WUR foo (int);
EXTERN_C_FUNC int fo2 WUR (int); // error error error error
EXTERN_C_FUNC int foo (int) WUR;
======================================================================
So, if we insist on using the 'extern' keyword ('extern CC' idiom):
* If _GL_ATTRIBUTE_* expands to bracket syntax [[...]]
in both C and C++, there is one available position:
- between the function name and the parameter list.
* If _GL_ATTRIBUTE_* expands to __attribute__((...)) syntax
in both C and C++, there are several available positions:
- before the return type,
- between return type and function name,
- at the end of the declaration.
* If _GL_ATTRIBUTE_* expands to bracket syntax [[...]] in C and to
__attribute__((...)) syntax in C++, there is no available position:
it would need to come before 'extern' in C but after 'extern "C"'
in C++.
* If _GL_ATTRIBUTE_* expands to __attribute__((...)) syntax in C and
to bracket syntax [[...]] in C++, there is one available position:
- before the return type.
Whereas, if we use the 'EXTERN_C_FUNC' idiom, which conditionally
omits the 'extern' keyword:
* If _GL_ATTRIBUTE_* expands to bracket syntax [[...]]
in both C and C++, there are two available positions:
- before the return type,
- between the function name and the parameter list.
* If _GL_ATTRIBUTE_* expands to __attribute__((...)) syntax
in both C and C++, there are several available positions:
- before the return type,
- between return type and function name,
- at the end of the declaration.
* If _GL_ATTRIBUTE_* expands to bracket syntax [[...]] in C and to
__attribute__((...)) syntax in C++, there is one available position:
- before the return type.
* If _GL_ATTRIBUTE_* expands to __attribute__((...)) syntax in C and
to bracket syntax [[...]] in C++, there is one available position:
- before the return type.
The best choice is therefore to use the 'EXTERN_C_FUNC' idiom and
put the attributes before the return type. This works regardless
to what the _GL_ATTRIBUTE_* macros expand.
*/
/* Attributes in bracket syntax [[...]] vs. attributes in __attribute__((...))
syntax, in static/inline function definitions.
There are similar constraints as for function declarations. However, here,
we cannot omit the storage-class specifier. Therefore, the following rule
applies:
* The macros
_GL_ATTRIBUTE_CONST
_GL_ATTRIBUTE_DEPRECATED
_GL_ATTRIBUTE_MAYBE_UNUSED
_GL_ATTRIBUTE_NODISCARD
_GL_ATTRIBUTE_PURE
_GL_ATTRIBUTE_REPRODUCIBLE
_GL_ATTRIBUTE_UNSEQUENCED
which may expand to bracket syntax [[...]], must come first, before the
storage-class specifier.
* Other _GL_ATTRIBUTE_* macros, that expand to __attribute__((...)) syntax,
are better placed between the storage-class specifier and the return
type.
*/
/* Attributes in bracket syntax [[...]] vs. attributes in __attribute__((...))
syntax, in variable declarations.
At which position can they be placed?
(Last tested with gcc/g++ 14 and clang/clang++ 18.)
=========================== foo.c = foo.cc ===========================
#ifdef __cplusplus
# define CC "C"
#else
# define CC
#endif
#define BD [[__deprecated__]]
#define AD __attribute__ ((__deprecated__))
// gcc clang g++ clang++
BD extern CC int var; // error error
extern CC BD int var; // error error
extern CC int BD var; // warn error warn error
extern CC int var BD;
AD extern CC int var; // warn
extern CC AD int var;
extern CC int AD var;
extern CC int var AD;
BD extern CC int z[]; // error error
extern CC BD int z[]; // error error
extern CC int BD z[]; // warn error warn error
extern CC int z1 BD [];
extern CC int z[] BD; // warn error error
AD extern CC int z[]; // warn
extern CC AD int z[];
extern CC int AD z[];
extern CC int z2 AD []; // error error error error
extern CC int z[] AD;
======================================================================
* For non-array variables, the only good position is after the variable name,
that is, at the end of the declaration.
* For array variables, you will need to distinguish C and C++:
- In C, before the 'extern' keyword.
- In C++, between the 'extern "C"' and the variable's type.
*/
]dnl There is no _GL_ATTRIBUTE_ALIGNED; use stdalign's alignas instead.
[
/* _GL_ATTRIBUTE_ALLOC_SIZE ((N)) declares that the Nth argument of the function
is the size of the returned memory block.
_GL_ATTRIBUTE_ALLOC_SIZE ((M, N)) declares that the Mth argument multiplied
by the Nth argument of the function is the size of the returned memory block.
*/
/* Applies to: functions, pointer to functions, function types. */
#ifndef _GL_ATTRIBUTE_ALLOC_SIZE
# if _GL_HAS_ATTRIBUTE (alloc_size)
# define _GL_ATTRIBUTE_ALLOC_SIZE(args) __attribute__ ((__alloc_size__ args))
# else
# define _GL_ATTRIBUTE_ALLOC_SIZE(args)
# endif
#endif
/* _GL_ATTRIBUTE_ALWAYS_INLINE tells that the compiler should always inline the
function and report an error if it cannot do so. */
/* Applies to: functions. */
#ifndef _GL_ATTRIBUTE_ALWAYS_INLINE
# if _GL_HAS_ATTRIBUTE (always_inline)
# define _GL_ATTRIBUTE_ALWAYS_INLINE __attribute__ ((__always_inline__))
# else
# define _GL_ATTRIBUTE_ALWAYS_INLINE
# endif
#endif
/* _GL_ATTRIBUTE_ARTIFICIAL declares that the function is not important to show
in stack traces when debugging. The compiler should omit the function from
stack traces. */
/* Applies to: functions. */
#ifndef _GL_ATTRIBUTE_ARTIFICIAL
# if _GL_HAS_ATTRIBUTE (artificial)
# define _GL_ATTRIBUTE_ARTIFICIAL __attribute__ ((__artificial__))
# else
# define _GL_ATTRIBUTE_ARTIFICIAL
# endif
#endif
/* _GL_ATTRIBUTE_COLD declares that the function is rarely executed. */
/* Applies to: functions. */
/* Avoid __attribute__ ((cold)) on MinGW; see thread starting at
<https://lists.gnu.org/r/emacs-devel/2019-04/msg01152.html>.
Also, Oracle Studio 12.6 requires 'cold' not '__cold__'. */
#ifndef _GL_ATTRIBUTE_COLD
# if _GL_HAS_ATTRIBUTE (cold) && !defined __MINGW32__
# ifndef __SUNPRO_C
# define _GL_ATTRIBUTE_COLD __attribute__ ((__cold__))
# else
# define _GL_ATTRIBUTE_COLD __attribute__ ((cold))
# endif
# else
# define _GL_ATTRIBUTE_COLD
# endif
#endif
/* _GL_ATTRIBUTE_CONST declares:
It is OK for a compiler to move calls to the function and to omit
calls to the function if another call has the same arguments or the
result is not used.
This attribute is safe for a function that neither depends on
nor affects state, and always returns exactly once -
e.g., does not raise an exception, call longjmp, or loop forever.
(This attribute is stricter than _GL_ATTRIBUTE_PURE because the
function cannot observe state. It is stricter than
_GL_ATTRIBUTE_UNSEQUENCED because the function must return exactly
once and cannot depend on state addressed by its arguments.) */
/* Applies to: functions. */
#ifndef _GL_ATTRIBUTE_CONST
# if _GL_HAS_ATTRIBUTE (const)
# define _GL_ATTRIBUTE_CONST __attribute__ ((__const__))
# else
# define _GL_ATTRIBUTE_CONST _GL_ATTRIBUTE_UNSEQUENCED
# endif
#endif
/* _GL_ATTRIBUTE_DEALLOC (F, I) declares that the function returns pointers
that can be freed by passing them as the Ith argument to the
function F.
_GL_ATTRIBUTE_DEALLOC_FREE declares that the function returns pointers that
can be freed via 'free'; it can be used only after declaring 'free'. */
/* Applies to: functions. Cannot be used on inline functions. */
#ifndef _GL_ATTRIBUTE_DEALLOC
# if _GL_GNUC_PREREQ (11, 0)
# define _GL_ATTRIBUTE_DEALLOC(f, i) __attribute__ ((__malloc__ (f, i)))
# else
# define _GL_ATTRIBUTE_DEALLOC(f, i)
# endif
#endif
/* If gnulib's <string.h> or <wchar.h> has already defined this macro, continue
to use this earlier definition, since <stdlib.h> may not have been included
yet. */
#ifndef _GL_ATTRIBUTE_DEALLOC_FREE
# if defined __cplusplus && defined __GNUC__ && !defined __clang__
/* Work around GCC bug <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108231> */
# define _GL_ATTRIBUTE_DEALLOC_FREE \
_GL_ATTRIBUTE_DEALLOC ((void (*) (void *)) free, 1)
# else
# define _GL_ATTRIBUTE_DEALLOC_FREE \
_GL_ATTRIBUTE_DEALLOC (free, 1)
# endif
#endif
/* _GL_ATTRIBUTE_DEPRECATED: Declares that an entity is deprecated.
The compiler may warn if the entity is used. */
/* Applies to:
- function, variable,
- struct, union, struct/union member,
- enumeration, enumeration item,
- typedef,
in C++ also: namespace, class, template specialization. */
#ifndef _GL_ATTRIBUTE_DEPRECATED
# ifndef _GL_BRACKET_BEFORE_ATTRIBUTE
# if _GL_HAVE___HAS_C_ATTRIBUTE
# if __has_c_attribute (__deprecated__)
# define _GL_ATTRIBUTE_DEPRECATED [[__deprecated__]]
# endif
# endif
# endif
# if !defined _GL_ATTRIBUTE_DEPRECATED && _GL_HAS_ATTRIBUTE (deprecated)
# define _GL_ATTRIBUTE_DEPRECATED __attribute__ ((__deprecated__))
# endif
# ifndef _GL_ATTRIBUTE_DEPRECATED
# define _GL_ATTRIBUTE_DEPRECATED
# endif
#endif
/* _GL_ATTRIBUTE_ERROR(msg) requests an error if a function is called and
the function call is not optimized away.
_GL_ATTRIBUTE_WARNING(msg) requests a warning if a function is called and
the function call is not optimized away. */
/* Applies to: functions. */
#if !(defined _GL_ATTRIBUTE_ERROR && defined _GL_ATTRIBUTE_WARNING)
# if _GL_HAS_ATTRIBUTE (error)
# define _GL_ATTRIBUTE_ERROR(msg) __attribute__ ((__error__ (msg)))
# define _GL_ATTRIBUTE_WARNING(msg) __attribute__ ((__warning__ (msg)))
# elif _GL_HAS_ATTRIBUTE (diagnose_if)
# define _GL_ATTRIBUTE_ERROR(msg) __attribute__ ((__diagnose_if__ (1, msg, "error")))
# define _GL_ATTRIBUTE_WARNING(msg) __attribute__ ((__diagnose_if__ (1, msg, "warning")))
# else
# define _GL_ATTRIBUTE_ERROR(msg)
# define _GL_ATTRIBUTE_WARNING(msg)
# endif
#endif
/* _GL_ATTRIBUTE_EXTERNALLY_VISIBLE declares that the entity should remain
visible to debuggers etc., even with '-fwhole-program'. */
/* Applies to: functions, variables. */
#ifndef _GL_ATTRIBUTE_EXTERNALLY_VISIBLE
# if _GL_HAS_ATTRIBUTE (externally_visible)
# define _GL_ATTRIBUTE_EXTERNALLY_VISIBLE __attribute__ ((externally_visible))
# else
# define _GL_ATTRIBUTE_EXTERNALLY_VISIBLE
# endif
#endif
/* _GL_ATTRIBUTE_FALLTHROUGH declares that it is not a programming mistake if
the control flow falls through to the immediately following 'case' or
'default' label. The compiler should not warn in this case. */
/* Applies to: Empty statement (;), inside a 'switch' statement. */
/* Always expands to something. */
#ifndef _GL_ATTRIBUTE_FALLTHROUGH
# if _GL_HAVE___HAS_C_ATTRIBUTE
# if __has_c_attribute (__fallthrough__)
# define _GL_ATTRIBUTE_FALLTHROUGH [[__fallthrough__]]
# endif
# endif
# if !defined _GL_ATTRIBUTE_FALLTHROUGH && _GL_HAS_ATTRIBUTE (fallthrough)
# define _GL_ATTRIBUTE_FALLTHROUGH __attribute__ ((__fallthrough__))
# endif
# ifndef _GL_ATTRIBUTE_FALLTHROUGH
# define _GL_ATTRIBUTE_FALLTHROUGH ((void) 0)
# endif
#endif
/* _GL_ATTRIBUTE_FORMAT ((ARCHETYPE, STRING-INDEX, FIRST-TO-CHECK))
declares that the STRING-INDEXth function argument is a format string of
style ARCHETYPE, which is one of:
printf, gnu_printf
scanf, gnu_scanf,
strftime, gnu_strftime,
strfmon,
or the same thing prefixed and suffixed with '__'.
If FIRST-TO-CHECK is not 0, arguments starting at FIRST-TO_CHECK
are suitable for the format string. */
/* Applies to: functions. */
#ifndef _GL_ATTRIBUTE_FORMAT
# if _GL_HAS_ATTRIBUTE (format)
# define _GL_ATTRIBUTE_FORMAT(spec) __attribute__ ((__format__ spec))
# else
# define _GL_ATTRIBUTE_FORMAT(spec)
# endif
#endif
/* _GL_ATTRIBUTE_LEAF declares that if the function is called from some other
compilation unit, it executes code from that unit only by return or by
exception handling. This declaration lets the compiler optimize that unit
more aggressively. */
/* Applies to: functions. */
#ifndef _GL_ATTRIBUTE_LEAF
# if _GL_HAS_ATTRIBUTE (leaf)
# define _GL_ATTRIBUTE_LEAF __attribute__ ((__leaf__))
# else
# define _GL_ATTRIBUTE_LEAF
# endif
#endif
/* _GL_ATTRIBUTE_MALLOC declares that the function returns a pointer to freshly
allocated memory. */
/* Applies to: functions. */
#ifndef _GL_ATTRIBUTE_MALLOC
# if _GL_HAS_ATTRIBUTE (malloc)
# define _GL_ATTRIBUTE_MALLOC __attribute__ ((__malloc__))
# else
# define _GL_ATTRIBUTE_MALLOC
# endif
#endif
/* _GL_ATTRIBUTE_MAY_ALIAS declares that pointers to the type may point to the
same storage as pointers to other types. Thus this declaration disables
strict aliasing optimization. */
/* Applies to: types. */
/* Oracle Studio 12.6 mishandles may_alias despite __has_attribute OK. */
#ifndef _GL_ATTRIBUTE_MAY_ALIAS
# if _GL_HAS_ATTRIBUTE (may_alias) && !defined __SUNPRO_C
# define _GL_ATTRIBUTE_MAY_ALIAS __attribute__ ((__may_alias__))
# else
# define _GL_ATTRIBUTE_MAY_ALIAS
# endif
#endif
/* _GL_ATTRIBUTE_MAYBE_UNUSED declares that it is not a programming mistake if
the entity is not used. The compiler should not warn if the entity is not
used. */
/* Applies to:
- function, variable,
- struct, union, struct/union member,
- enumeration, enumeration item,
- typedef,
in C++ also: class. */
/* In C++ and C23, this is spelled [[__maybe_unused__]].
GCC's syntax is __attribute__ ((__unused__)).
clang supports both syntaxes. Except that with clang ≥ 6, < 10, in C++ mode,
__has_c_attribute (__maybe_unused__) yields true but the use of
[[__maybe_unused__]] nevertheless produces a warning. */
#ifndef _GL_ATTRIBUTE_MAYBE_UNUSED
# ifndef _GL_BRACKET_BEFORE_ATTRIBUTE
# if defined __clang__ && defined __cplusplus
# if !defined __apple_build_version__ && __clang_major__ >= 10
# define _GL_ATTRIBUTE_MAYBE_UNUSED [[__maybe_unused__]]
# endif
# elif _GL_HAVE___HAS_C_ATTRIBUTE
# if __has_c_attribute (__maybe_unused__)
# define _GL_ATTRIBUTE_MAYBE_UNUSED [[__maybe_unused__]]
# endif
# endif
# endif
# ifndef _GL_ATTRIBUTE_MAYBE_UNUSED
# define _GL_ATTRIBUTE_MAYBE_UNUSED _GL_ATTRIBUTE_UNUSED
# endif
#endif
/* Alternative spelling of this macro, for convenience and for
compatibility with glibc/include/libc-symbols.h. */
#define _GL_UNUSED _GL_ATTRIBUTE_MAYBE_UNUSED
/* Earlier spellings of this macro. */
#define _UNUSED_PARAMETER_ _GL_ATTRIBUTE_MAYBE_UNUSED
/* _GL_ATTRIBUTE_NODISCARD declares that the caller of the function should not
discard the return value. The compiler may warn if the caller does not use
the return value, unless the caller uses something like ignore_value. */
/* Applies to: function, enumeration, class. */
#ifndef _GL_ATTRIBUTE_NODISCARD
# ifndef _GL_BRACKET_BEFORE_ATTRIBUTE
# if defined __clang__ && defined __cplusplus
/* With clang up to 15.0.6 (at least), in C++ mode, [[__nodiscard__]] produces
a warning.
The 1000 below means a yet unknown threshold. When clang++ version X
starts supporting [[__nodiscard__]] without warning about it, you can
replace the 1000 with X. */
# if __clang_major__ >= 1000
# define _GL_ATTRIBUTE_NODISCARD [[__nodiscard__]]
# endif
# elif _GL_HAVE___HAS_C_ATTRIBUTE
# if __has_c_attribute (__nodiscard__)
# define _GL_ATTRIBUTE_NODISCARD [[__nodiscard__]]
# endif
# endif
# endif
# if !defined _GL_ATTRIBUTE_NODISCARD && _GL_HAS_ATTRIBUTE (warn_unused_result)
# define _GL_ATTRIBUTE_NODISCARD __attribute__ ((__warn_unused_result__))
# endif
# ifndef _GL_ATTRIBUTE_NODISCARD
# define _GL_ATTRIBUTE_NODISCARD
# endif
#endif
/* _GL_ATTRIBUTE_NOINLINE tells that the compiler should not inline the
function. */
/* Applies to: functions. */
#ifndef _GL_ATTRIBUTE_NOINLINE
# if _GL_HAS_ATTRIBUTE (noinline)
# define _GL_ATTRIBUTE_NOINLINE __attribute__ ((__noinline__))
# else
# define _GL_ATTRIBUTE_NOINLINE
# endif
#endif
/* _GL_ATTRIBUTE_NONNULL ((N1, N2,...)) declares that the arguments N1, N2,...
must not be NULL.
_GL_ATTRIBUTE_NONNULL () declares that all pointer arguments must not be
null. */
/* Applies to: functions. */
#ifndef _GL_ATTRIBUTE_NONNULL
# if _GL_HAS_ATTRIBUTE (nonnull)
# define _GL_ATTRIBUTE_NONNULL(args) __attribute__ ((__nonnull__ args))
# else
# define _GL_ATTRIBUTE_NONNULL(args)
# endif
#endif
/* _GL_ATTRIBUTE_NONSTRING declares that the contents of a character array is
not meant to be NUL-terminated. */
/* Applies to: struct/union members and variables that are arrays of element
type '[[un]signed] char'. */
#ifndef _GL_ATTRIBUTE_NONSTRING
# if _GL_HAS_ATTRIBUTE (nonstring)
# define _GL_ATTRIBUTE_NONSTRING __attribute__ ((__nonstring__))
# else
# define _GL_ATTRIBUTE_NONSTRING
# endif
#endif
/* There is no _GL_ATTRIBUTE_NORETURN; use _Noreturn instead. */
/* _GL_ATTRIBUTE_NOTHROW declares that the function does not throw exceptions.
*/
/* Applies to: functions. */
/* After a function's parameter list, this attribute must come first, before
other attributes. */
#ifndef _GL_ATTRIBUTE_NOTHROW
# if defined __cplusplus
# if _GL_GNUC_PREREQ (2, 8) || __clang_major__ >= 4
# if __cplusplus >= 201103L
# define _GL_ATTRIBUTE_NOTHROW noexcept (true)
# else
# define _GL_ATTRIBUTE_NOTHROW throw ()
# endif
# else
# define _GL_ATTRIBUTE_NOTHROW
# endif
# else
# if _GL_HAS_ATTRIBUTE (nothrow)
# define _GL_ATTRIBUTE_NOTHROW __attribute__ ((__nothrow__))
# else
# define _GL_ATTRIBUTE_NOTHROW
# endif
# endif
#endif
/* _GL_ATTRIBUTE_PACKED declares:
For struct members: The member has the smallest possible alignment.
For struct, union, class: All members have the smallest possible alignment,
minimizing the memory required. */
/* Applies to: struct members, struct, union,
in C++ also: class. */
#ifndef _GL_ATTRIBUTE_PACKED
/* Oracle Studio 12.6 miscompiles code with __attribute__ ((__packed__)) despite
__has_attribute OK. */
# if _GL_HAS_ATTRIBUTE (packed) && !defined __SUNPRO_C
# define _GL_ATTRIBUTE_PACKED __attribute__ ((__packed__))
# else
# define _GL_ATTRIBUTE_PACKED
# endif
#endif
/* _GL_ATTRIBUTE_PURE declares:
It is OK for a compiler to move calls to the function and to omit
calls to the function if another call has the same arguments or the
result is not used, and if observable state is the same.
This attribute is safe for a function that does not affect observable state
and always returns exactly once.
(This attribute is looser than _GL_ATTRIBUTE_CONST because the function
can depend on observable state. It is stricter than
_GL_ATTRIBUTE_REPRODUCIBLE because the function must return exactly
once and cannot affect state addressed by its arguments.) */
/* Applies to: functions. */
#ifndef _GL_ATTRIBUTE_PURE
# if _GL_HAS_ATTRIBUTE (pure)
# define _GL_ATTRIBUTE_PURE __attribute__ ((__pure__))
# else
# define _GL_ATTRIBUTE_PURE _GL_ATTRIBUTE_REPRODUCIBLE
# endif
#endif
/* _GL_ATTRIBUTE_REPRODUCIBLE declares:
It is OK for a compiler to move calls to the function and to omit duplicate
calls to the function with the same arguments, so long as the state
addressed by its arguments is the same and is updated in time for
the rest of the program.
This attribute is safe for a function that is effectless and idempotent; see
ISO C 23 § 6.7.12.7 for a definition of these terms.
(This attribute is looser than _GL_ATTRIBUTE_UNSEQUENCED because
the function need not be stateless and idempotent. It is looser
than _GL_ATTRIBUTE_PURE because the function need not return
exactly once and can affect state addressed by its arguments.)
See also <https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2956.htm> and
<https://stackoverflow.com/questions/76847905/>.
ATTENTION! Efforts are underway to change the meaning of this attribute.
See <https://www.open-std.org/jtc1/sc22/wg14/www/docs/n3424.htm>. */
/* Applies to: functions, pointer to functions, function types. */
#ifndef _GL_ATTRIBUTE_REPRODUCIBLE
/* This may be revisited when gcc and clang support [[reproducible]] or possibly
__attribute__ ((__reproducible__)). */
# ifndef _GL_BRACKET_BEFORE_ATTRIBUTE
# if _GL_HAS_ATTRIBUTE (reproducible)
# define _GL_ATTRIBUTE_REPRODUCIBLE [[reproducible]]
# endif
# endif
# ifndef _GL_ATTRIBUTE_REPRODUCIBLE
# define _GL_ATTRIBUTE_REPRODUCIBLE
# endif
#endif
/* _GL_ATTRIBUTE_RETURNS_NONNULL declares that the function's return value is
a non-NULL pointer. */
/* Applies to: functions. */
#ifndef _GL_ATTRIBUTE_RETURNS_NONNULL
# if _GL_HAS_ATTRIBUTE (returns_nonnull)
# define _GL_ATTRIBUTE_RETURNS_NONNULL __attribute__ ((__returns_nonnull__))
# else
# define _GL_ATTRIBUTE_RETURNS_NONNULL
# endif
#endif
/* _GL_ATTRIBUTE_SENTINEL(pos) declares that the variadic function expects a
trailing NULL argument.
_GL_ATTRIBUTE_SENTINEL () - The last argument is NULL (requires C99).
_GL_ATTRIBUTE_SENTINEL ((N)) - The (N+1)st argument from the end is NULL. */
/* Applies to: functions. */
#ifndef _GL_ATTRIBUTE_SENTINEL
# if _GL_HAS_ATTRIBUTE (sentinel)
# define _GL_ATTRIBUTE_SENTINEL(pos) __attribute__ ((__sentinel__ pos))
# else
# define _GL_ATTRIBUTE_SENTINEL(pos)
# endif
#endif
/* _GL_ATTRIBUTE_UNSEQUENCED declares:
It is OK for a compiler to move calls to the function and to omit duplicate
calls to the function with the same arguments, so long as the state
addressed by its arguments is the same.
This attribute is safe for a function that is effectless, idempotent,
stateless, and independent; see ISO C 23 § 6.7.12.7 for a definition of
these terms.
(This attribute is stricter than _GL_ATTRIBUTE_REPRODUCIBLE because
the function must be stateless and independent. It is looser than
_GL_ATTRIBUTE_CONST because the function need not return exactly
once and can depend on state addressed by its arguments.)
See also <https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2956.htm> and
<https://stackoverflow.com/questions/76847905/>.
ATTENTION! Efforts are underway to change the meaning of this attribute.
See <https://www.open-std.org/jtc1/sc22/wg14/www/docs/n3424.htm>. */
/* Applies to: functions, pointer to functions, function types. */
#ifndef _GL_ATTRIBUTE_UNSEQUENCED
/* This may be revisited when gcc and clang support [[unsequenced]] or possibly
__attribute__ ((__unsequenced__)). */
# ifndef _GL_BRACKET_BEFORE_ATTRIBUTE
# if _GL_HAS_ATTRIBUTE (unsequenced)
# define _GL_ATTRIBUTE_UNSEQUENCED [[unsequenced]]
# endif
# endif
# ifndef _GL_ATTRIBUTE_UNSEQUENCED
# define _GL_ATTRIBUTE_UNSEQUENCED
# endif
#endif
/* A helper macro. Don't use it directly. */
#ifndef _GL_ATTRIBUTE_UNUSED
# if _GL_HAS_ATTRIBUTE (unused)
# define _GL_ATTRIBUTE_UNUSED __attribute__ ((__unused__))
# else
# define _GL_ATTRIBUTE_UNUSED
# endif
#endif
]dnl There is no _GL_ATTRIBUTE_VISIBILITY; see m4/visibility.m4 instead.
[
/* _GL_UNUSED_LABEL; declares that it is not a programming mistake if the
immediately preceding label is not used. The compiler should not warn
if the label is not used. */
/* Applies to: label (both in C and C++). */
/* Note that g++ < 4.5 does not support the '__attribute__ ((__unused__)) ;'
syntax. But clang does. */
#ifndef _GL_UNUSED_LABEL
# if !(defined __cplusplus && !_GL_GNUC_PREREQ (4, 5)) || defined __clang__
# define _GL_UNUSED_LABEL _GL_ATTRIBUTE_UNUSED
# else
# define _GL_UNUSED_LABEL
# endif
#endif
/* The following attributes enable detection of multithread-safety problems
and resource leaks at compile-time, by clang ≥ 15, when the warning option
-Wthread-safety is enabled. For usage, see
<https://clang.llvm.org/docs/ThreadSafetyAnalysis.html>. */
#ifndef _GL_ATTRIBUTE_CAPABILITY_TYPE
# if __clang_major__ >= 15
# define _GL_ATTRIBUTE_CAPABILITY_TYPE(concept) \
__attribute__ ((__capability__ (concept)))
# else
# define _GL_ATTRIBUTE_CAPABILITY_TYPE(concept)
# endif
#endif
#ifndef _GL_ATTRIBUTE_ACQUIRE_CAPABILITY
# if __clang_major__ >= 15
# define _GL_ATTRIBUTE_ACQUIRE_CAPABILITY(resource) \
__attribute__ ((__acquire_capability__ (resource)))
# else
# define _GL_ATTRIBUTE_ACQUIRE_CAPABILITY(resource)
# endif
#endif
#ifndef _GL_ATTRIBUTE_RELEASE_CAPABILITY
# if __clang_major__ >= 15
# define _GL_ATTRIBUTE_RELEASE_CAPABILITY(resource) \
__attribute__ ((__release_capability__ (resource)))
# else
# define _GL_ATTRIBUTE_RELEASE_CAPABILITY(resource)
# endif
#endif
])
AH_VERBATIM([c_linkage],
[/* In C++, there is the concept of "language linkage", that encompasses
name mangling and function calling conventions.
The following macros start and end a block of "C" linkage. */
#ifdef __cplusplus
# define _GL_BEGIN_C_LINKAGE extern "C" {
# define _GL_END_C_LINKAGE }
#else
# define _GL_BEGIN_C_LINKAGE
# define _GL_END_C_LINKAGE
#endif
])
AH_VERBATIM([async_safe],
[/* The _GL_ASYNC_SAFE marker should be attached to functions that are
signal handlers (for signals other than SIGABRT, SIGPIPE) or can be
invoked from such signal handlers. Such functions have some restrictions:
* All functions that it calls should be marked _GL_ASYNC_SAFE as well,
or should be listed as async-signal-safe in POSIX
<https://pubs.opengroup.org/onlinepubs/9699919799/functions/V2_chap02.html#tag_15_04>
section 2.4.3. Note that malloc(), sprintf(), and fwrite(), in
particular, are NOT async-signal-safe.
* All memory locations (variables and struct fields) that these functions
access must be marked 'volatile'. This holds for both read and write
accesses. Otherwise the compiler might optimize away stores to and
reads from such locations that occur in the program, depending on its
data flow analysis. For example, when the program contains a loop
that is intended to inspect a variable set from within a signal handler
while (!signal_occurred)
;
the compiler is allowed to transform this into an endless loop if the
variable 'signal_occurred' is not declared 'volatile'.
Additionally, recall that:
* A signal handler should not modify errno (except if it is a handler
for a fatal signal and ends by raising the same signal again, thus
provoking the termination of the process). If it invokes a function
that may clobber errno, it needs to save and restore the value of
errno. */
#define _GL_ASYNC_SAFE
])
AH_VERBATIM([micro_optimizations],
[/* _GL_CMP (n1, n2) performs a three-valued comparison on n1 vs. n2, where
n1 and n2 are expressions without side effects, that evaluate to real
numbers (excluding NaN).
It returns
1 if n1 > n2
0 if n1 == n2
-1 if n1 < n2
The naïve code (n1 > n2 ? 1 : n1 < n2 ? -1 : 0) produces a conditional
jump with nearly all GCC versions up to GCC 10.
This variant (n1 < n2 ? -1 : n1 > n2) produces a conditional with many
GCC versions up to GCC 9.
The better code (n1 > n2) - (n1 < n2) from Hacker's Delight § 2-9
avoids conditional jumps in all GCC versions >= 3.4. */
#define _GL_CMP(n1, n2) (((n1) > (n2)) - ((n1) < (n2)))
])
dnl Hint which direction to take regarding cross-compilation guesses:
dnl When a user installs a program on a platform they are not intimately
dnl familiar with, --enable-cross-guesses=conservative is the appropriate
dnl choice. It implements the "If we don't know, assume the worst" principle.
dnl However, when an operating system developer (on a platform which is not
dnl yet known to gnulib) builds packages for their platform, they want to
dnl expose, not hide, possible platform bugs; in this case,
dnl --enable-cross-guesses=risky is the appropriate choice.
dnl Sets the variables
dnl gl_cross_guess_normal (to be used when 'yes' is good and 'no' is bad),
dnl gl_cross_guess_inverted (to be used when 'no' is good and 'yes' is bad).
AC_ARG_ENABLE([cross-guesses],
[AS_HELP_STRING([[--enable-cross-guesses={conservative|risky}]],
[specify policy for cross-compilation guesses])],
[if test "x$enableval" != xconservative && test "x$enableval" != xrisky; then
AC_MSG_WARN([invalid argument supplied to --enable-cross-guesses])
enableval=conservative
fi
gl_cross_guesses="$enableval"],
[gl_cross_guesses=conservative])
if test $gl_cross_guesses = risky; then
gl_cross_guess_normal="guessing yes"
gl_cross_guess_inverted="guessing no"
else
gl_cross_guess_normal="guessing no"
gl_cross_guess_inverted="guessing yes"
fi
dnl Preparation for running test programs:
dnl Tell glibc to write diagnostics from -D_FORTIFY_SOURCE=2 to stderr, not
dnl to /dev/tty, so they can be redirected to log files. Such diagnostics
dnl arise e.g., in the macros gl_PRINTF_DIRECTIVE_N, gl_SNPRINTF_DIRECTIVE_N.
LIBC_FATAL_STDERR_=1
export LIBC_FATAL_STDERR_
])
# gl_MODULE_INDICATOR_INIT_VARIABLE([variablename])
# gl_MODULE_INDICATOR_INIT_VARIABLE([variablename], [initialvalue])
# initializes the shell variable that indicates the presence of the given module
# as a C preprocessor expression.
AC_DEFUN([gl_MODULE_INDICATOR_INIT_VARIABLE],
[
GL_MODULE_INDICATOR_PREFIX[]_[$1]=m4_if([$2], , [0], [$2])
AC_SUBST(GL_MODULE_INDICATOR_PREFIX[]_[$1])
])
# gl_MODULE_INDICATOR_CONDITION
# expands to a C preprocessor expression that evaluates to 1 or 0, depending
# whether a gnulib module that has been requested shall be considered present
# or not.
m4_define([gl_MODULE_INDICATOR_CONDITION], [1])
# gl_MODULE_INDICATOR_SET_VARIABLE([modulename])
# sets the shell variable that indicates the presence of the given module to
# a C preprocessor expression that will evaluate to 1.
AC_DEFUN([gl_MODULE_INDICATOR_SET_VARIABLE],
[
gl_MODULE_INDICATOR_SET_VARIABLE_AUX(
[GL_MODULE_INDICATOR_PREFIX[]_GNULIB_[]m4_translit([[$1]],
[abcdefghijklmnopqrstuvwxyz./-],
[ABCDEFGHIJKLMNOPQRSTUVWXYZ___])],
[gl_MODULE_INDICATOR_CONDITION])
])
# gl_MODULE_INDICATOR_SET_VARIABLE_AUX([variable])
# modifies the shell variable to include the gl_MODULE_INDICATOR_CONDITION.
# The shell variable's value is a C preprocessor expression that evaluates