iconv.m4

# iconv.m4
# serial 28
dnl Copyright (C) 2000-2002, 2007-2014, 2016-2024 Free Software Foundation,
dnl 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.

dnl From Bruno Haible.

AC_PREREQ([2.64])

dnl Note: AM_ICONV is documented in the GNU gettext manual
dnl <https://www.gnu.org/software/gettext/manual/html_node/AM_005fICONV.html>.
dnl Don't make changes that are incompatible with that documentation!

AC_DEFUN([AM_ICONV_LINKFLAGS_BODY],
[
  dnl Prerequisites of AC_LIB_LINKFLAGS_BODY.
  AC_REQUIRE([AC_LIB_PREPARE_PREFIX])
  AC_REQUIRE([AC_LIB_RPATH])

  dnl Search for libiconv and define LIBICONV, LTLIBICONV and INCICONV
  dnl accordingly.
  AC_LIB_LINKFLAGS_BODY([iconv])
])

AC_DEFUN([AM_ICONV_LINK],
[
  dnl Some systems have iconv in libc, some have it in libiconv (OSF/1 and
  dnl those with the standalone portable GNU libiconv installed).
  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles

  dnl Search for libiconv and define LIBICONV, LTLIBICONV and INCICONV
  dnl accordingly.
  AC_REQUIRE([AM_ICONV_LINKFLAGS_BODY])

  dnl Add $INCICONV to CPPFLAGS before performing the following checks,
  dnl because if the user has installed libiconv and not disabled its use
  dnl via --without-libiconv-prefix, he wants to use it. The first
  dnl AC_LINK_IFELSE will then fail, the second AC_LINK_IFELSE will succeed.
  gl_saved_CPPFLAGS="$CPPFLAGS"
  AC_LIB_APPENDTOVAR([CPPFLAGS], [$INCICONV])

  AC_CACHE_CHECK([for iconv], [am_cv_func_iconv], [
    am_cv_func_iconv="no, consider installing GNU libiconv"
    am_cv_lib_iconv=no
    AC_LINK_IFELSE(
      [AC_LANG_PROGRAM(
         [[
#include <stdlib.h>
#include <iconv.h>
         ]],
         [[iconv_t cd = iconv_open("","");
           iconv(cd,NULL,NULL,NULL,NULL);
           iconv_close(cd);]])],
      [am_cv_func_iconv=yes])
    if test "$am_cv_func_iconv" != yes; then
      gl_saved_LIBS="$LIBS"
      LIBS="$LIBS $LIBICONV"
      AC_LINK_IFELSE(
        [AC_LANG_PROGRAM(
           [[
#include <stdlib.h>
#include <iconv.h>
           ]],
           [[iconv_t cd = iconv_open("","");
             iconv(cd,NULL,NULL,NULL,NULL);
             iconv_close(cd);]])],
        [am_cv_lib_iconv=yes]
        [am_cv_func_iconv=yes])
      LIBS="$gl_saved_LIBS"
    fi
  ])
  if test "$am_cv_func_iconv" = yes; then
    AC_CACHE_CHECK([for working iconv], [am_cv_func_iconv_works], [
      dnl This tests against bugs in AIX 5.1, AIX 6.1..7.1, HP-UX 11.11,
      dnl Solaris 10, macOS 14.4.
      gl_saved_LIBS="$LIBS"
      if test $am_cv_lib_iconv = yes; then
        LIBS="$LIBS $LIBICONV"
      fi
      am_cv_func_iconv_works=no
      for ac_iconv_const in '' 'const'; do
        AC_RUN_IFELSE(
          [AC_LANG_PROGRAM(
             [[
#include <iconv.h>
#include <string.h>

#ifndef ICONV_CONST
# define ICONV_CONST $ac_iconv_const
#endif
             ]],
             [[int result = 0;
  /* Test against AIX 5.1...7.2 bug: Failures are not distinguishable from
     successful returns.  This is even documented in
     <https://www.ibm.com/support/knowledgecenter/ssw_aix_72/i_bostechref/iconv.html> */
  {
    iconv_t cd_utf8_to_88591 = iconv_open ("ISO8859-1", "UTF-8");
    if (cd_utf8_to_88591 != (iconv_t)(-1))
      {
        static ICONV_CONST char input[] = "\342\202\254"; /* EURO SIGN */
        char buf[10];
        ICONV_CONST char *inptr = input;
        size_t inbytesleft = strlen (input);
        char *outptr = buf;
        size_t outbytesleft = sizeof (buf);
        size_t res = iconv (cd_utf8_to_88591,
                            &inptr, &inbytesleft,
                            &outptr, &outbytesleft);
        if (res == 0)
          result |= 1;
        iconv_close (cd_utf8_to_88591);
      }
  }
  /* Test against macOS 14.4 bug: Failures are not distinguishable from
     successful returns.
     POSIX:2018 says: "The iconv() function shall ... return the number of
     non-identical conversions performed."
     But here, the conversion always does transliteration (the suffixes
     "//TRANSLIT" and "//IGNORE" have no effect, nor does iconvctl()) and
     does not report when it does a non-identical conversion.  */
  {
    iconv_t cd_utf8_to_88591 = iconv_open ("ISO-8859-1", "UTF-8");
    if (cd_utf8_to_88591 != (iconv_t)(-1))
      {
        static ICONV_CONST char input[] = "\305\202"; /* LATIN SMALL LETTER L WITH STROKE */
        char buf[10];
        ICONV_CONST char *inptr = input;
        size_t inbytesleft = strlen (input);
        char *outptr = buf;
        size_t outbytesleft = sizeof (buf);
        size_t res = iconv (cd_utf8_to_88591,
                            &inptr, &inbytesleft,
                            &outptr, &outbytesleft);
        /* Here:
           With glibc, GNU libiconv (including macOS up to 13): res == (size_t)-1, errno == EILSEQ.
           With musl libc, NetBSD 10, Solaris 11: res == 1.
           With macOS 14.4: res == 0, output is "l".  */
        if (res == 0)
          result |= 2;
        iconv_close (cd_utf8_to_88591);
      }
  }
  /* Test against Solaris 10 bug: Failures are not distinguishable from
     successful returns.  */
  {
    iconv_t cd_ascii_to_88591 = iconv_open ("ISO8859-1", "646");
    if (cd_ascii_to_88591 != (iconv_t)(-1))
      {
        static ICONV_CONST char input[] = "\263";
        char buf[10];
        ICONV_CONST char *inptr = input;
        size_t inbytesleft = strlen (input);
        char *outptr = buf;
        size_t outbytesleft = sizeof (buf);
        size_t res = iconv (cd_ascii_to_88591,
                            &inptr, &inbytesleft,
                            &outptr, &outbytesleft);
        if (res == 0)
          result |= 4;
        iconv_close (cd_ascii_to_88591);
      }
  }
  /* Test against AIX 6.1..7.1 bug: Buffer overrun.  */
  {
    iconv_t cd_88591_to_utf8 = iconv_open ("UTF-8", "ISO-8859-1");
    if (cd_88591_to_utf8 != (iconv_t)(-1))
      {
        static ICONV_CONST char input[] = "\304";
        static char buf[2] = { (char)0xDE, (char)0xAD };
        ICONV_CONST char *inptr = input;
        size_t inbytesleft = 1;
        char *outptr = buf;
        size_t outbytesleft = 1;
        size_t res = iconv (cd_88591_to_utf8,
                            &inptr, &inbytesleft,
                            &outptr, &outbytesleft);
        if (res != (size_t)(-1) || outptr - buf > 1 || buf[1] != (char)0xAD)
          result |= 8;
        iconv_close (cd_88591_to_utf8);
      }
  }
#if 0 /* This bug could be worked around by the caller.  */
  /* Test against HP-UX 11.11 bug: Positive return value instead of 0.  */
  {
    iconv_t cd_88591_to_utf8 = iconv_open ("utf8", "iso88591");
    if (cd_88591_to_utf8 != (iconv_t)(-1))
      {
        static ICONV_CONST char input[] = "\304rger mit b\366sen B\374bchen ohne Augenma\337";
        char buf[50];
        ICONV_CONST char *inptr = input;
        size_t inbytesleft = strlen (input);
        char *outptr = buf;
        size_t outbytesleft = sizeof (buf);
        size_t res = iconv (cd_88591_to_utf8,
                            &inptr, &inbytesleft,
                            &outptr, &outbytesleft);
        if ((int)res > 0)
          result |= 16;
        iconv_close (cd_88591_to_utf8);
      }
  }
#endif
  /* Test against HP-UX 11.11 bug: No converter from EUC-JP to UTF-8 is
     provided.  */
  {
    /* Try standardized names.  */
    iconv_t cd1 = iconv_open ("UTF-8", "EUC-JP");
    /* Try IRIX, OSF/1 names.  */
    iconv_t cd2 = iconv_open ("UTF-8", "eucJP");
    /* Try AIX names.  */
    iconv_t cd3 = iconv_open ("UTF-8", "IBM-eucJP");
    /* Try HP-UX names.  */
    iconv_t cd4 = iconv_open ("utf8", "eucJP");
    if (cd1 == (iconv_t)(-1) && cd2 == (iconv_t)(-1)
        && cd3 == (iconv_t)(-1) && cd4 == (iconv_t)(-1))
      result |= 32;
    if (cd1 != (iconv_t)(-1))
      iconv_close (cd1);
    if (cd2 != (iconv_t)(-1))
      iconv_close (cd2);
    if (cd3 != (iconv_t)(-1))
      iconv_close (cd3);
    if (cd4 != (iconv_t)(-1))
      iconv_close (cd4);
  }
  return result;
]])],
          [am_cv_func_iconv_works=yes], ,
          [case "$host_os" in
             aix* | hpux*) am_cv_func_iconv_works="guessing no" ;;
             *)            am_cv_func_iconv_works="guessing yes" ;;
           esac])
        test "$am_cv_func_iconv_works" = no || break
      done
      LIBS="$gl_saved_LIBS"
    ])
    case "$am_cv_func_iconv_works" in
      *no) am_func_iconv=no am_cv_lib_iconv=no ;;
      *)   am_func_iconv=yes ;;
    esac
  else
    am_func_iconv=no am_cv_lib_iconv=no
  fi
  if test "$am_func_iconv" = yes; then
    AC_DEFINE([HAVE_ICONV], [1],
      [Define if you have the iconv() function and it works.])
  fi
  if test "$am_cv_lib_iconv" = yes; then
    AC_MSG_CHECKING([how to link with libiconv])
    AC_MSG_RESULT([$LIBICONV])
  else
    dnl If $LIBICONV didn't lead to a usable library, we don't need $INCICONV
    dnl either.
    CPPFLAGS="$gl_saved_CPPFLAGS"
    LIBICONV=
    LTLIBICONV=
  fi
  AC_SUBST([LIBICONV])
  AC_SUBST([LTLIBICONV])
])

dnl Define AM_ICONV using AC_DEFUN_ONCE, in order to avoid warnings like
dnl "warning: AC_REQUIRE: `AM_ICONV' was expanded before it was required".
AC_DEFUN_ONCE([AM_ICONV],
[
  AM_ICONV_LINK
  if test "$am_cv_func_iconv" = yes; then
    AC_CACHE_CHECK([whether iconv is compatible with its POSIX signature],
      [gl_cv_iconv_nonconst],
      [AC_COMPILE_IFELSE(
         [AC_LANG_PROGRAM(
            [[
#include <stdlib.h>
#include <iconv.h>
extern
#ifdef __cplusplus
"C"
#endif
size_t iconv (iconv_t cd, char * *inbuf, size_t *inbytesleft, char * *outbuf, size_t *outbytesleft);
            ]],
            [[]])],
         [gl_cv_iconv_nonconst=yes],
         [gl_cv_iconv_nonconst=no])
      ])
  else
    dnl When compiling GNU libiconv on a system that does not have iconv yet,
    dnl pick the POSIX compliant declaration without 'const'.
    gl_cv_iconv_nonconst=yes
  fi
  if test $gl_cv_iconv_nonconst = yes; then
    iconv_arg1=""
  else
    iconv_arg1="const"
  fi
  AC_DEFINE_UNQUOTED([ICONV_CONST], [$iconv_arg1],
    [Define as const if the declaration of iconv() needs const.])
  dnl Also substitute ICONV_CONST in the gnulib generated <iconv.h>.
  m4_ifdef([gl_ICONV_H_DEFAULTS],
    [AC_REQUIRE([gl_ICONV_H_DEFAULTS])
     if test $gl_cv_iconv_nonconst != yes; then
       ICONV_CONST="const"
     fi
    ])

  dnl A summary result, for those packages which want to print a summary at the
  dnl end of the configuration.
  if test "$am_func_iconv" = yes; then
    if test -n "$LIBICONV"; then
      am_cv_func_iconv_summary='yes, in libiconv'
    else
      am_cv_func_iconv_summary='yes, in libc'
    fi
  else
    if test "$am_cv_func_iconv" = yes; then
      am_cv_func_iconv_summary='not working, consider installing GNU libiconv'
    else
      am_cv_func_iconv_summary='no, consider installing GNU libiconv'
    fi
  fi
])