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      1 # btowc.m4 serial 12
      2 dnl Copyright (C) 2008-2022 Free Software Foundation, Inc.
      3 dnl This file is free software; the Free Software Foundation
      4 dnl gives unlimited permission to copy and/or distribute it,
      5 dnl with or without modifications, as long as this notice is preserved.
      6 
      7 AC_DEFUN([gl_FUNC_BTOWC],
      8 [
      9   AC_REQUIRE([gl_WCHAR_H_DEFAULTS])
     10 
     11   dnl Check whether <wchar.h> is usable at all, first. Otherwise the test
     12   dnl program below may lead to an endless loop. See
     13   dnl <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=42440>.
     14   AC_REQUIRE([gl_WCHAR_H_INLINE_OK])
     15 
     16   AC_CHECK_FUNCS_ONCE([btowc])
     17   if test $ac_cv_func_btowc = no; then
     18     HAVE_BTOWC=0
     19   else
     20 
     21     AC_REQUIRE([AC_PROG_CC])
     22     AC_REQUIRE([gt_LOCALE_FR])
     23     AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
     24 
     25     dnl Cygwin 1.7.2 btowc('\0') is WEOF, not 0.
     26     AC_CACHE_CHECK([whether btowc(0) is correct],
     27       [gl_cv_func_btowc_nul],
     28       [
     29         AC_RUN_IFELSE(
     30           [AC_LANG_SOURCE([[
     31 #include <wchar.h>
     32 int main ()
     33 {
     34   if (btowc ('\0') != 0)
     35     return 1;
     36   return 0;
     37 }]])],
     38           [gl_cv_func_btowc_nul=yes],
     39           [gl_cv_func_btowc_nul=no],
     40           [
     41 changequote(,)dnl
     42            case "$host_os" in
     43                       # Guess no on Cygwin.
     44              cygwin*) gl_cv_func_btowc_nul="guessing no" ;;
     45                       # Guess yes on native Windows.
     46              mingw*)  gl_cv_func_btowc_nul="guessing yes" ;;
     47                       # Guess yes otherwise.
     48              *)       gl_cv_func_btowc_nul="guessing yes" ;;
     49            esac
     50 changequote([,])dnl
     51           ])
     52       ])
     53 
     54     dnl IRIX 6.5 btowc(EOF) is 0xFF, not WEOF.
     55     AC_CACHE_CHECK([whether btowc(EOF) is correct],
     56       [gl_cv_func_btowc_eof],
     57       [
     58         dnl Initial guess, used when cross-compiling or when no suitable locale
     59         dnl is present.
     60 changequote(,)dnl
     61         case "$host_os" in
     62                   # Guess no on IRIX.
     63           irix*)  gl_cv_func_btowc_eof="guessing no" ;;
     64                   # Guess yes on native Windows.
     65           mingw*) gl_cv_func_btowc_eof="guessing yes" ;;
     66                   # Guess yes otherwise.
     67           *)      gl_cv_func_btowc_eof="guessing yes" ;;
     68         esac
     69 changequote([,])dnl
     70         if test $LOCALE_FR != none; then
     71           AC_RUN_IFELSE(
     72             [AC_LANG_SOURCE([[
     73 #include <locale.h>
     74 #include <stdio.h>
     75 #include <wchar.h>
     76 int main ()
     77 {
     78   if (setlocale (LC_ALL, "$LOCALE_FR") != NULL)
     79     {
     80       if (btowc (EOF) != WEOF)
     81         return 1;
     82     }
     83   return 0;
     84 }]])],
     85             [gl_cv_func_btowc_eof=yes],
     86             [gl_cv_func_btowc_eof=no],
     87             [:])
     88         fi
     89       ])
     90 
     91     case "$gl_cv_func_btowc_nul" in
     92       *yes) ;;
     93       *) REPLACE_BTOWC=1 ;;
     94     esac
     95     case "$gl_cv_func_btowc_eof" in
     96       *yes) ;;
     97       *) REPLACE_BTOWC=1 ;;
     98     esac
     99   fi
    100 ])
    101 
    102 # Prerequisites of lib/btowc.c.
    103 AC_DEFUN([gl_PREREQ_BTOWC], [
    104   :
    105 ])
    106