newlib/libc/stdlib/wctomb.c

   1 /*
   2 FUNCTION
   3 <<wctomb>>---minimal wide char to multibyte converter
   4
   5 INDEX
   6         wctomb
   7
   8 SYNOPSIS
   9         #include <stdlib.h>
  10         int wctomb(char *<[s]>, wchar_t <[wchar]>);
  11
  12 DESCRIPTION
  13 When _MB_CAPABLE is not defined, this is a minimal ANSI-conforming
  14 implementation of <<wctomb>>.  The
  15 only ``wide characters'' recognized are single bytes,
  16 and they are ``converted'' to themselves.
  17
  18 When _MB_CAPABLE is defined, this routine calls <<_wctomb_r>> to perform
  19 the conversion, passing a state variable to allow state dependent
  20 decoding.  The result is based on the locale setting which may
  21 be restricted to a defined set of locales.
  22
  23 Each call to <<wctomb>> modifies <<*<[s]>>> unless <[s]> is a null
  24 pointer or _MB_CAPABLE is defined and <[wchar]> is invalid.
  25
  26 RETURNS
  27 This implementation of <<wctomb>> returns <<0>> if
  28 <[s]> is <<NULL>>; it returns <<-1>> if _MB_CAPABLE is enabled
  29 and the wchar is not a valid multi-byte character, it returns <<1>>
  30 if _MB_CAPABLE is not defined or the wchar is in reality a single
  31 byte character, otherwise it returns the number of bytes in the
  32 multi-byte character.
  33
  34 PORTABILITY
  35 <<wctomb>> is required in the ANSI C standard.  However, the precise
  36 effects vary with the locale.
  37
  38 <<wctomb>> requires no supporting OS subroutines.
  39 */
  40
  41 #ifndef _REENT_ONLY
  42
  43 #include <newlib.h>
  44 #include <stdlib.h>
  45 #include <errno.h>
  46 #include "local.h"
  47
  48 #ifdef _REENT_THREAD_LOCAL
  49 _Thread_local _mbstate_t _tls_wctomb_state;
  50 #endif
  51
  52 int
  53 wctomb (char *s,
  54         wchar_t wchar)
  55 {
  56 #ifdef _MB_CAPABLE
  57         struct _reent *reent = _REENT;
  58
  59         _REENT_CHECK_MISC(reent);
  60
  61         return __WCTOMB (reent, s, wchar, &(_REENT_WCTOMB_STATE(reent)));
  62 #else /* not _MB_CAPABLE */
  63         if (s == NULL)
  64                 return 0;
  65
  66         /* Verify that wchar is a valid single-byte character.  */
  67         if ((size_t)wchar >= 0x100) {
  68                 errno = EILSEQ;
  69                 return -1;
  70         }
  71
  72         *s = (char) wchar;
  73         return 1;
  74 #endif /* not _MB_CAPABLE */
  75 }
  76
  77 #endif /* !_REENT_ONLY */