wcrtomb_s
Convert a wide character into its multibyte character representation. A version of wcrtomb with security enhancements as described in Security Features in the CRT.
errno_t wcrtomb_s( size_t *pReturnValue, char *mbchar, size_t sizeOfmbchar, wchar_t *wchar, mbstate_t *mbstate ); template <size_t size> errno_t wcrtomb_s( size_t *pReturnValue, char (&mbchar)[size], wchar_t *wchar, mbstate_t *mbstate ); // C++ only
The wcrtomb_s function converts a wide character, beginning in the specified conversion state contained in mbstate, from the value contained in wchar, into the address represented by mbchar. The pReturnValue value will be the number of bytes converted, but no more than MB_CUR_MAX bytes, or an -1 if an error occurred.
If mbstate is null, the internal mbstate_t conversion state is used. If the character contained in wchar does not have a corresponding multibyte character, the value of pReturnValue will be -1 and the function will return the errno value of EILSEQ.
The wcrtomb_s function differs from wctomb_s, _wctomb_s_l by its restartability. The conversion state is stored in mbstate for subsequent calls to the same or other restartable functions. Results are undefined when mixing the use of restartable and nonrestartable functions. For example, an application would use wcsrlen rather than wcslen, if a subsequent call to wcsrtombs_s were used instead of wcstombs_s.
In C++, using this function is simplified by template overloads; the overloads can infer buffer length automatically (eliminating the need to specify a size argument) and they can automatically replace older, non-secure functions with their newer, secure counterparts. For more information, see Secure Template Overloads.
// crt_wcrtomb_s.c
// This program converts a wide character
// to its corresponding multibyte character.
//
#include <string.h>
#include <stdio.h>
#include <wchar.h>
int main( void )
{
errno_t returnValue;
size_t pReturnValue;
mbstate_t mbstate;
size_t sizeOfmbStr = 1;
char mbchar = 0;
wchar_t* wchar = L"Q\0";
// Reset to initial conversion state
memset(&mbstate, 0, sizeof(mbstate));
returnValue = wcrtomb_s(&pReturnValue, &mbchar, sizeof(char),
*wchar, &mbstate);
if (returnValue == 0) {
printf("The corresponding wide character \"");
wprintf(L"%s\"", wchar);
printf(" was converted to a the \"%c\" ", mbchar);
printf("multibyte character.\n");
}
else
{
printf("No corresponding multibyte character "
"was found.\n");
}
}
The corresponding wide character "Q" was converted to a the "Q" multibyte character.
Not applicable. To call the standard C function, use PInvoke. For more information, see Platform Invoke Examples.
