283
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1 # Check for stdbool.h that conforms to C99.
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2
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3 dnl Copyright (C) 2002-2006 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__ || defined __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. We also test
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90 this with GCC, where it should work, to detect more
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91 quickly whether someone messes up the test in the
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92 future. */
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93 char digs[] = "0123456789";
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94 int xlcbug = 1 / (&(digs + 5)[-2 + (bool) 1] == &digs[4] ? 1 : -1);
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95 #endif
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96 /* Catch a bug in an HP-UX C compiler. See
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97 http://gcc.gnu.org/ml/gcc-patches/2003-12/msg02303.html
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98 http://lists.gnu.org/archive/html/bug-coreutils/2005-11/msg00161.html
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99 */
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100 _Bool q = true;
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101 _Bool *pq = &q;
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102 ],
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103 [
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104 *pq |= q;
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105 *pq |= ! q;
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106 /* Refer to every declared value, to avoid compiler optimizations. */
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107 return (!a + !b + !c + !d + !e + !f + !g + !h + !i + !!j + !k + !!l
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108 + !m + !n + !o + !p + !q + !pq);
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109 ],
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110 [ac_cv_header_stdbool_h=yes],
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111 [ac_cv_header_stdbool_h=no])])
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112 AC_CHECK_TYPES([_Bool])
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113 if test $ac_cv_header_stdbool_h = yes; then
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114 AC_DEFINE(HAVE_STDBOOL_H, 1, [Define to 1 if stdbool.h conforms to C99.])
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115 fi])
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