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