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# btowc.m4
# serial 16
dnl Copyright (C) 2008-2025 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
dnl with or without modifications, as long as this notice is preserved.
dnl This file is offered as-is, without any warranty.
AC_DEFUN([gl_FUNC_BTOWC],
[
AC_REQUIRE([gl_WCHAR_H_DEFAULTS])
AC_REQUIRE([gt_TYPE_WINT_T])
dnl Check whether <wchar.h> is usable at all, first. Otherwise the test
dnl program below may lead to an endless loop. See
dnl <https://gcc.gnu.org/PR42440>.
AC_REQUIRE([gl_WCHAR_H_INLINE_OK])
AC_CHECK_FUNCS_ONCE([btowc])
if test $ac_cv_func_btowc = no; then
HAVE_BTOWC=0
else
AC_REQUIRE([AC_PROG_CC])
AC_REQUIRE([gt_LOCALE_FR])
AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
dnl Cygwin 1.7.2 btowc('\0') is WEOF, not 0.
AC_CACHE_CHECK([whether btowc(0) is correct],
[gl_cv_func_btowc_nul],
[
AC_RUN_IFELSE(
[AC_LANG_SOURCE([[
#include <wchar.h>
int main ()
{
if (btowc ('\0') != 0)
return 1;
return 0;
}]])],
[gl_cv_func_btowc_nul=yes],
[gl_cv_func_btowc_nul=no],
[
changequote(,)dnl
case "$host_os" in
# Guess no on Cygwin.
cygwin*) gl_cv_func_btowc_nul="guessing no" ;;
# Guess yes on native Windows.
mingw* | windows*) gl_cv_func_btowc_nul="guessing yes" ;;
# Guess yes otherwise.
*) gl_cv_func_btowc_nul="guessing yes" ;;
esac
changequote([,])dnl
])
])
dnl On mingw, in the C locale, btowc is inconsistent with mbrtowc:
dnl mbrtowc avoids calling MultiByteToWideChar when MB_CUR_MAX is 1 and
dnl ___lc_codepage_func() is 0, but btowc is lacking this special case.
AC_CHECK_FUNCS_ONCE([mbrtowc])
AC_CACHE_CHECK([whether btowc is consistent with mbrtowc in the C locale],
[gl_cv_func_btowc_consistent],
[
AC_RUN_IFELSE(
[AC_LANG_SOURCE([[
#include <stdlib.h>
#include <string.h>
#include <wchar.h>
int main ()
{
#if HAVE_MBRTOWC
wint_t wc1 = btowc (0x80);
wchar_t wc2 = (wchar_t) 0xbadface;
char buf[1] = { 0x80 };
mbstate_t state;
memset (&state, 0, sizeof (mbstate_t));
if (mbrtowc (&wc2, buf, 1, &state) != 1 || wc1 != wc2)
return 1;
#endif
return 0;
}]])],
[gl_cv_func_btowc_consistent=yes],
[gl_cv_func_btowc_consistent=no],
[case "$host_os" in
# Guess no on mingw.
mingw* | windows*)
AC_EGREP_CPP([Problem], [
#ifdef __MINGW32__
Problem
#endif
],
[gl_cv_func_btowc_consistent="guessing no"],
[gl_cv_func_btowc_consistent="guessing yes"])
;;
# Guess yes otherwise.
*) gl_cv_func_btowc_consistent="guessing yes" ;;
esac
])
])
if test $GNULIBHEADERS_OVERRIDE_WINT_T = 1; then
dnl On mingw/ucrt, we override the return type of btowc().
dnl While the original wint_t (= unsigned short) and the overridden wint_t
dnl (= unsigned int) are equivalent in function parameters, this is not
dnl the case for function return types.
REPLACE_BTOWC=1
fi
case "$gl_cv_func_btowc_nul" in
*yes) ;;
*) REPLACE_BTOWC=1 ;;
esac
case "$gl_cv_func_btowc_consistent" in
*yes) ;;
*) REPLACE_BTOWC=1 ;;
esac
if test $REPLACE_BTOWC = 0; then
gl_MBRTOWC_C_LOCALE
case "$gl_cv_func_mbrtowc_C_locale_sans_EILSEQ" in
*yes) ;;
*) REPLACE_BTOWC=1 ;;
esac
fi
fi
])
# Prerequisites of lib/btowc.c.
AC_DEFUN([gl_PREREQ_BTOWC], [
:
AC_CHECK_FUNCS_ONCE([mbrtowc])
])
|
