stdlib/wctomb.c

   1 /* Copyright (C) 1991-2024 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <https://www.gnu.org/licenses/>.  */
  17
  18 #include <stdlib.h>
  19 #include <string.h>
  20 #include <wchar.h>
  21 #include <gconv.h>
  22 #include <wcsmbs/wcsmbsload.h>
  23
  24
  25 /* Shared with __wctomb_chk.  */
  26 mbstate_t __wctomb_state attribute_hidden;
  27
  28 /* Convert WCHAR into its multibyte character representation,
  29    putting this in S and returning its length.
  30
  31    Attention: this function should NEVER be intentionally used.
  32    The interface is completely stupid.  The state is shared between
  33    all conversion functions.  You should use instead the restartable
  34    version `wcrtomb'.  */
  35 int
  36 wctomb (char *s, wchar_t wchar)
  37 {
  38   /* If S is NULL the function has to return null or not null
  39      depending on the encoding having a state depending encoding or
  40      not.  */
  41   if (s == NULL)
  42     {
  43       const struct gconv_fcts *fcts;
  44
  45       /* Get the conversion functions.  */
  46       fcts = get_gconv_fcts (_NL_CURRENT_DATA (LC_CTYPE));
  47
  48       /* This is an extension in the Unix standard which does not directly
  49          violate ISO C.  */
  50       memset (&__wctomb_state, '\0', sizeof __wctomb_state);
  51
  52       return fcts->tomb->__stateful;
  53     }
  54
  55   return __wcrtomb (s, wchar, &__wctomb_state);
  56 }
  57 libc_hidden_def (wctomb)