wctomb_s, _wctomb_s_l

Converts a wide character to the corresponding multibyte character. A version of wctomb, _wctomb_l with security enhancements as described in Security features in the CRT.

Syntax

errno_t wctomb_s(
   int *pRetValue,
   char *mbchar,
   size_t sizeInBytes,
   wchar_t wchar
);
errno_t _wctomb_s_l(
   int *pRetValue,
   char *mbchar,
   size_t sizeInBytes,
   wchar_t wchar,
   _locale_t locale
);

Parameters

pRetValue
The number of bytes, or a code indicating the result.

mbchar
The address of a multibyte character.

sizeInBytes
Size of the buffer mbchar.

wchar
The wide character to convert.

locale
The locale to use.

Return value

Zero if successful, an error code on failure.

Error Conditions

mbchar	sizeInBytes	Return value	pRetValue
NULL	>0	EINVAL	not modified
any	>INT_MAX	EINVAL	not modified
any	too small	EINVAL	not modified

If any of the above error conditions occurs, the invalid parameter handler is invoked, as described in Parameter validation. If execution is allowed to continue, wctomb returns EINVAL and sets errno to EINVAL.

The return value EILSEQ indicates that the value passed via the parameter wchar is not a valid wide character.

Remarks

The wctomb_s function converts its wchar argument to the corresponding multibyte character and stores the result at mbchar. You can call the function from any point in any program.

If wctomb_s converts the wide character to a multibyte character, it puts the number of bytes (which is never greater than MB_CUR_MAX) in the wide character into the integer pointed to by pRetValue. If wchar is the wide-character null character (L'\0'), wctomb_s fills pRetValue with 1. If the target pointer mbchar is NULL, wctomb_s puts 0 in pRetValue. If the conversion isn't possible in the current locale, wctomb_s puts -1 in pRetValue.

wctomb_s uses the current locale for locale-dependent information; _wctomb_s_l is identical except that it uses the locale passed in instead. For more information, see Locale.

By default, this function's global state is scoped to the application. To change this behavior, see Global state in the CRT.

Requirements

Routine	Required header
wctomb_s	<stdlib.h>
_wctomb_s_l	<stdlib.h>

For more compatibility information, see Compatibility.

Example

This program illustrates the behavior of the wctomb_s function.

// crt_wctomb_s.cpp
#include <stdio.h>
#include <stdlib.h>

int main( void )
{
    int i;
    wchar_t wc = L'a';
    char *pmb = (char *)malloc( MB_CUR_MAX );

    printf_s( "Convert a wide character:\n" );
    wctomb_s( &i, pmb, MB_CUR_MAX, wc );
    printf_s( "   Characters converted: %u\n", i );
    printf_s( "   Multibyte character: %.1s\n\n", pmb );
}

Convert a wide character:
   Characters converted: 1
   Multibyte character: a

See also

Data conversion
Locale
_mbclen, mblen, _mblen_l
mbstowcs, _mbstowcs_l
mbtowc, _mbtowc_l
wcstombs, _wcstombs_l
WideCharToMultiByte