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libiconv 1.16

    1: # Check for stdbool.h that conforms to C99.
    2: 
    3: dnl Copyright (C) 2002-2006, 2009-2019 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: #serial 7
    9: 
   10: # Prepare for substituting <stdbool.h> if it is not supported.
   11: 
   12: AC_DEFUN([AM_STDBOOL_H],
   13: [
   14:   AC_REQUIRE([AC_CHECK_HEADER_STDBOOL])
   15: 
   16:   # Define two additional variables used in the Makefile substitution.
   17: 
   18:   if test "$ac_cv_header_stdbool_h" = yes; then
   19:     STDBOOL_H=''
   20:   else
   21:     STDBOOL_H='stdbool.h'
   22:   fi
   23:   AC_SUBST([STDBOOL_H])
   24:   AM_CONDITIONAL([GL_GENERATE_STDBOOL_H], [test -n "$STDBOOL_H"])
   25: 
   26:   if test "$ac_cv_type__Bool" = yes; then
   27:     HAVE__BOOL=1
   28:   else
   29:     HAVE__BOOL=0
   30:   fi
   31:   AC_SUBST([HAVE__BOOL])
   32: ])
   33: 
   34: # AM_STDBOOL_H will be renamed to gl_STDBOOL_H in the future.
   35: AC_DEFUN([gl_STDBOOL_H], [AM_STDBOOL_H])
   36: 
   37: # This version of the macro is needed in autoconf <= 2.68.
   38: 
   39: AC_DEFUN([AC_CHECK_HEADER_STDBOOL],
   40:   [AC_CACHE_CHECK([for stdbool.h that conforms to C99],
   41:      [ac_cv_header_stdbool_h],
   42:      [AC_COMPILE_IFELSE(
   43:         [AC_LANG_PROGRAM(
   44:            [[
   45:              #include <stdbool.h>
   46: 
   47:              #ifdef __cplusplus
   48:               typedef bool Bool;
   49:              #else
   50:               typedef _Bool Bool;
   51:               #ifndef bool
   52:                "error: bool is not defined"
   53:               #endif
   54:               #ifndef false
   55:                "error: false is not defined"
   56:               #endif
   57:               #if false
   58:                "error: false is not 0"
   59:               #endif
   60:               #ifndef true
   61:                "error: true is not defined"
   62:               #endif
   63:               #if true != 1
   64:                "error: true is not 1"
   65:               #endif
   66:              #endif
   67: 
   68:              #ifndef __bool_true_false_are_defined
   69:               "error: __bool_true_false_are_defined is not defined"
   70:              #endif
   71: 
   72:              struct s { Bool s: 1; Bool t; bool u: 1; bool v; } s;
   73: 
   74:              char a[true == 1 ? 1 : -1];
   75:              char b[false == 0 ? 1 : -1];
   76:              char c[__bool_true_false_are_defined == 1 ? 1 : -1];
   77:              char d[(bool) 0.5 == true ? 1 : -1];
   78:              /* See body of main program for 'e'.  */
   79:              char f[(Bool) 0.0 == false ? 1 : -1];
   80:              char g[true];
   81:              char h[sizeof (Bool)];
   82:              char i[sizeof s.t];
   83:              enum { j = false, k = true, l = false * true, m = true * 256 };
   84:              /* The following fails for
   85:                 HP aC++/ANSI C B3910B A.05.55 [Dec 04 2003]. */
   86:              Bool n[m];
   87:              char o[sizeof n == m * sizeof n[0] ? 1 : -1];
   88:              char p[-1 - (Bool) 0 < 0 && -1 - (bool) 0 < 0 ? 1 : -1];
   89:              /* Catch a bug in an HP-UX C compiler.  See
   90:                 https://gcc.gnu.org/ml/gcc-patches/2003-12/msg02303.html
   91:                 https://lists.gnu.org/r/bug-coreutils/2005-11/msg00161.html
   92:               */
   93:              Bool q = true;
   94:              Bool *pq = &q;
   95:              bool *qq = &q;
   96:            ]],
   97:            [[
   98:              bool e = &s;
   99:              *pq |= q; *pq |= ! q;
  100:              *qq |= q; *qq |= ! q;
  101:              /* Refer to every declared value, to avoid compiler optimizations.  */
  102:              return (!a + !b + !c + !d + !e + !f + !g + !h + !i + !!j + !k + !!l
  103:                      + !m + !n + !o + !p + !q + !pq + !qq);
  104:            ]])],
  105:         [ac_cv_header_stdbool_h=yes],
  106:         [ac_cv_header_stdbool_h=no])])
  107:    AC_CHECK_TYPES([_Bool])
  108: ])