# wcwidth.m4
# serial 39
dnl Copyright (C) 2006-2025 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_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_WINT_T])

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

  AC_CHECK_DECLS([wcwidth], [], [], [[
    #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
    AC_CACHE_CHECK([whether wcwidth is a macro],
      [gl_cv_func_wcwidth_macro],
      [AC_EGREP_CPP([wchar_header_defines_wcwidth], [
#include <wchar.h>
#ifdef wcwidth
 wchar_header_defines_wcwidth
#endif],
         [gl_cv_func_wcwidth_macro=yes],
         [gl_cv_func_wcwidth_macro=no])
      ])
  fi

  if test $ac_cv_func_wcwidth = yes || test $gl_cv_func_wcwidth_macro = yes; then
    HAVE_WCWIDTH=1
    dnl On Mac OS X 10.3, wcwidth(0x0301) (COMBINING ACUTE ACCENT) returns 1.
    dnl On macOS 12.5, NetBSD 9.3, OpenBSD 5.0, MidnightBSD 1.1,
    dnl wcwidth(0x05B0) (HEBREW POINT SHEVA) returns 1.
    dnl On macOS 12.5, NetBSD 9.3, MidnightBSD 1.1,
    dnl wcwidth(0x200B) (ZERO WIDTH SPACE) returns 1.
    dnl On OpenBSD 5.8, wcwidth(0xFF1A) (FULLWIDTH COLON) returns 0.
    dnl This leads to bugs in 'ls' (coreutils).
    dnl On Solaris 11.4, wcwidth(0x2202) (PARTIAL DIFFERENTIAL) returns 2,
    dnl even in Western locales.
    AC_CACHE_CHECK([whether wcwidth works reasonably in UTF-8 locales],
      [gl_cv_func_wcwidth_works],
      [
        AC_RUN_IFELSE(
          [AC_LANG_SOURCE([[
#include <locale.h>
#include <wchar.h>
#if !HAVE_DECL_WCWIDTH
extern
# ifdef __cplusplus
"C"
# endif
int wcwidth (int);
#endif
int main ()
{
  int result = 0;
  if (setlocale (LC_ALL, "en_US.UTF-8") != NULL)
    {
      if (wcwidth (0x0301) > 0)
        result |= 1;
      if (wcwidth (0x05B0) > 0)
        result |= 2;
      if (wcwidth (0x200B) > 0)
        result |= 4;
      if (wcwidth (0xFF1A) == 0)
        result |= 8;
      if (wcwidth (0x2202) > 1)
        result |= 16;
    }
  return result;
}]])],
          [gl_cv_func_wcwidth_works=yes],
          [gl_cv_func_wcwidth_works=no],
          [
changequote(,)dnl
           case "$host_os" in
                                 # Guess yes on glibc systems.
             *-gnu* | gnu*)      gl_cv_func_wcwidth_works="guessing yes";;
                                 # Guess yes on musl systems.
             *-musl* | midipix*) gl_cv_func_wcwidth_works="guessing yes";;
                                 # Guess yes on AIX 7 systems.
             aix[7-9]*)          gl_cv_func_wcwidth_works="guessing yes";;
             *)                  gl_cv_func_wcwidth_works="$gl_cross_guess_normal";;
           esac
changequote([,])dnl
          ])
      ])
    case "$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.
])

# Prerequisites of lib/wcwidth.c.
AC_DEFUN([gl_PREREQ_WCWIDTH], [
  AC_REQUIRE([AC_C_INLINE])
  :
])
