texinfo/gnulib/m4/wcwidth.m4

# wcwidth.m4 serial 23
dnl Copyright (C) 2006-2017 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.

AC_DEFUN([gl_FUNC_WCWIDTH],
[
  AC_REQUIRE([gl_WCHAR_H_DEFAULTS])
  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles

  dnl Persuade glibc <wchar.h> to declare wcwidth().
  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])

  AC_REQUIRE([gt_TYPE_WCHAR_T])
  AC_REQUIRE([gt_TYPE_WINT_T])

  AC_CHECK_HEADERS_ONCE([wchar.h])
  AC_CHECK_FUNCS_ONCE([wcwidth])

  AC_CHECK_DECLS([wcwidth], [], [], [[
/* AIX 3.2.5 declares wcwidth in <string.h>. */
#include <string.h>
/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
   <wchar.h>.
   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be included
   before <wchar.h>.  */
#include <stddef.h>
#include <stdio.h>
#include <time.h>
#include <wchar.h>
]])
  if test $ac_cv_have_decl_wcwidth != yes; then
    HAVE_DECL_WCWIDTH=0
  fi

  if test $ac_cv_func_wcwidth = yes; then
    HAVE_WCWIDTH=1
    dnl On Mac OS X 10.3, wcwidth(0x0301) (COMBINING ACUTE ACCENT) returns 1.
    dnl On OpenBSD 5.0, wcwidth(0x05B0) (HEBREW POINT SHEVA) returns 1.
    dnl On OSF/1 5.1, wcwidth(0x200B) (ZERO WIDTH SPACE) returns 1.
    dnl On OpenBSD 5.8, wcwidth(0xFF1A) (FULLWIDTH COLON) returns 0.
    dnl This leads to bugs in 'ls' (coreutils).
    AC_CACHE_CHECK([whether wcwidth works reasonably in UTF-8 locales],
      [gl_cv_func_wcwidth_works],
      [
        AC_RUN_IFELSE(
          [AC_LANG_SOURCE([[
#include <locale.h>
/* AIX 3.2.5 declares wcwidth in <string.h>. */
#include <string.h>
/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
   <wchar.h>.
   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be included
   before <wchar.h>.  */
#include <stddef.h>
#include <stdio.h>
#include <time.h>
#include <wchar.h>
#if !HAVE_DECL_WCWIDTH
extern
# ifdef __cplusplus
"C"
# endif
int wcwidth (int);
#endif
int main ()
{
  int result = 0;
  if (setlocale (LC_ALL, "fr_FR.UTF-8") != NULL)
    {
      if (wcwidth (0x0301) > 0)
        result |= 1;
      if (wcwidth (0x05B0) > 0)
        result |= 2;
      if (wcwidth (0x200B) > 0)
        result |= 4;
      if (wcwidth (0xFF1A) == 0)
        result |= 8;
    }
  return result;
}]])],
          [gl_cv_func_wcwidth_works=yes],
          [gl_cv_func_wcwidth_works=no],
          [
changequote(,)dnl
           case "$host_os" in
                     # Guess yes on glibc and AIX 7 systems.
             *-gnu* | aix[7-9]*) gl_cv_func_wcwidth_works="guessing yes";;
             *)                  gl_cv_func_wcwidth_works="guessing no";;
           esac
changequote([,])dnl
          ])
      ])
    case "$gl_cv_func_wcwidth_works" in
      *yes) ;;
      *no) REPLACE_WCWIDTH=1 ;;
    esac
  else
    HAVE_WCWIDTH=0
  fi
  dnl We don't substitute HAVE_WCWIDTH. We assume that if the system does not
  dnl have the wcwidth function, then it does not declare it.
])