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e65fc94b LC |
1 | # Check for stdbool.h that conforms to C99. |
2 | ||
3 | dnl Copyright (C) 2002-2006 Free Software Foundation, Inc. | |
4 | dnl This file is free software; the Free Software Foundation | |
5 | dnl gives unlimited permission to copy and/or distribute it, | |
6 | dnl with or without modifications, as long as this notice is preserved. | |
7 | ||
8 | # Prepare for substituting <stdbool.h> if it is not supported. | |
9 | ||
10 | AC_DEFUN([AM_STDBOOL_H], | |
11 | [ | |
12 | AC_REQUIRE([AC_HEADER_STDBOOL]) | |
13 | ||
14 | # Define two additional variables used in the Makefile substitution. | |
15 | ||
16 | if test "$ac_cv_header_stdbool_h" = yes; then | |
17 | STDBOOL_H='' | |
18 | else | |
19 | STDBOOL_H='stdbool.h' | |
20 | fi | |
21 | AC_SUBST([STDBOOL_H]) | |
22 | ||
23 | if test "$ac_cv_type__Bool" = yes; then | |
24 | HAVE__BOOL=1 | |
25 | else | |
26 | HAVE__BOOL=0 | |
27 | fi | |
28 | AC_SUBST([HAVE__BOOL]) | |
29 | ]) | |
30 | ||
31 | # AM_STDBOOL_H will be renamed to gl_STDBOOL_H in the future. | |
32 | AC_DEFUN([gl_STDBOOL_H], [AM_STDBOOL_H]) | |
33 | ||
34 | # This macro is only needed in autoconf <= 2.59. Newer versions of autoconf | |
35 | # have this macro built-in. | |
36 | ||
37 | AC_DEFUN([AC_HEADER_STDBOOL], | |
38 | [AC_CACHE_CHECK([for stdbool.h that conforms to C99], | |
39 | [ac_cv_header_stdbool_h], | |
40 | [AC_TRY_COMPILE( | |
41 | [ | |
42 | #include <stdbool.h> | |
43 | #ifndef bool | |
44 | "error: bool is not defined" | |
45 | #endif | |
46 | #ifndef false | |
47 | "error: false is not defined" | |
48 | #endif | |
49 | #if false | |
50 | "error: false is not 0" | |
51 | #endif | |
52 | #ifndef true | |
53 | "error: true is not defined" | |
54 | #endif | |
55 | #if true != 1 | |
56 | "error: true is not 1" | |
57 | #endif | |
58 | #ifndef __bool_true_false_are_defined | |
59 | "error: __bool_true_false_are_defined is not defined" | |
60 | #endif | |
61 | ||
62 | struct s { _Bool s: 1; _Bool t; } s; | |
63 | ||
64 | char a[true == 1 ? 1 : -1]; | |
65 | char b[false == 0 ? 1 : -1]; | |
66 | char c[__bool_true_false_are_defined == 1 ? 1 : -1]; | |
67 | char d[(bool) 0.5 == true ? 1 : -1]; | |
68 | bool e = &s; | |
69 | char f[(_Bool) 0.0 == false ? 1 : -1]; | |
70 | char g[true]; | |
71 | char h[sizeof (_Bool)]; | |
72 | char i[sizeof s.t]; | |
73 | enum { j = false, k = true, l = false * true, m = true * 256 }; | |
74 | _Bool n[m]; | |
75 | char o[sizeof n == m * sizeof n[0] ? 1 : -1]; | |
76 | char p[-1 - (_Bool) 0 < 0 && -1 - (bool) 0 < 0 ? 1 : -1]; | |
77 | #if defined __xlc__ || defined __GNUC__ | |
78 | /* Catch a bug in IBM AIX xlc compiler version 6.0.0.0 | |
79 | reported by James Lemley on 2005-10-05; see | |
80 | http://lists.gnu.org/archive/html/bug-coreutils/2005-10/msg00086.html | |
81 | This test is not quite right, since xlc is allowed to | |
82 | reject this program, as the initializer for xlcbug is | |
83 | not one of the forms that C requires support for. | |
84 | However, doing the test right would require a run-time | |
85 | test, and that would make cross-compilation harder. | |
86 | Let us hope that IBM fixes the xlc bug, and also adds | |
87 | support for this kind of constant expression. In the | |
88 | meantime, this test will reject xlc, which is OK, since | |
89 | our stdbool.h substitute should suffice. We also test | |
90 | this with GCC, where it should work, to detect more | |
91 | quickly whether someone messes up the test in the | |
92 | future. */ | |
93 | char digs[] = "0123456789"; | |
94 | int xlcbug = 1 / (&(digs + 5)[-2 + (bool) 1] == &digs[4] ? 1 : -1); | |
95 | #endif | |
96 | /* Catch a bug in an HP-UX C compiler. See | |
97 | http://gcc.gnu.org/ml/gcc-patches/2003-12/msg02303.html | |
98 | http://lists.gnu.org/archive/html/bug-coreutils/2005-11/msg00161.html | |
99 | */ | |
100 | _Bool q = true; | |
101 | _Bool *pq = &q; | |
102 | ], | |
103 | [ | |
104 | *pq |= q; | |
105 | *pq |= ! q; | |
106 | /* Refer to every declared value, to avoid compiler optimizations. */ | |
107 | return (!a + !b + !c + !d + !e + !f + !g + !h + !i + !!j + !k + !!l | |
108 | + !m + !n + !o + !p + !q + !pq); | |
109 | ], | |
110 | [ac_cv_header_stdbool_h=yes], | |
111 | [ac_cv_header_stdbool_h=no])]) | |
112 | AC_CHECK_TYPES([_Bool]) | |
113 | if test $ac_cv_header_stdbool_h = yes; then | |
114 | AC_DEFINE(HAVE_STDBOOL_H, 1, [Define to 1 if stdbool.h conforms to C99.]) | |
115 | fi]) |