wcsrtombs

Name

wcsrtombs, wcsnrtombs
- convert a wide character string to a multibyte string

Library

libc.lib

Synopsis

#include <wchar.h>

size_t wcsrtombs (char * restrict dst, const wchar_t ** restrict src, size_t len, mbstate_t * restrict ps);

size_t wcsnrtombs (char * restrict dst, const wchar_t ** restrict src, size_t nwc, size_t len, ,, mbstate_t, *, restrict, ps);

Return values

The wcsrtombs and wcsnrtombs functions return the number of bytes stored in the array pointed to by dst (not including any terminating null), if successful, otherwise it returns (size_t-1).

Detailed description

The wcsrtombs function converts a string of wide characters indirectly pointed to by src to a corresponding multibyte character string stored in the array pointed to by dst. No more than len bytes are written to dst.

If dst is NULL, no characters are stored.

If dst is not NULL, the pointer pointed to by src is updated to point to the character after the one that conversion stopped at. If conversion stops because a null character is encountered, *src is set to NULL.

The mbstate_t argument, ps, is used to keep track of the shift state. If it is NULL, wcsrtombs uses an internal, static mbstate_t object, which is initialized to the initial conversion state at program startup.

The wcsnrtombs function behaves identically to wcsrtombs, except that conversion stops after reading at most nwc characters from the buffer pointed to by src. The behavior of the wcsrtombs and wcsrntombs is affected by LC_CTYPE category of the current locale.

Examples

#include <stdlib.h>
#include <wchar.h>
/* Illustrates how to use wcsrtombs API */
size_t example_wcsrtombs(wchar_t *wcs, char *s, size_t n)
{
 size_t len;
 mstate_t mbs;
 /* converting multibyte string to a wide-char string */
 len = wcsrtombs(s, &wcs, n, &mbs);
 /* returning no of bytes that make up the multibyte sequence */
 return (len;);
}

#include <stdlib.h>
#include <wchar.h>
/* Illustrates how to use wcsnrtombs API */
size_t example_wcsnrtombs(wchar_t *wcs, char *s, size_t n, szie_t nmwc)
{
 size_t len;
 mstate_t mbs;
 /* converting multibyte string to a wide-char string */
 len = wcsrtombs(s, &wcs, nwc, n, &mbs);
 /* returning no of bytes that make up the multibyte sequence */
 return (len;);
}

Errors

The wcsrtombs and wcsnrtombs functions will fail if:

[`EILSEQ`]
	An invalid wide character was encountered.
[`EINVAL`]
	The conversion state is invalid.

Limitations

The current implementation of wcsrtombs and wcsnrtombs is not affected by the LC_CTYPE category of the current locale. It works only for UTF8 character set.

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