MBSRTOWCS(3)

NAME
mbsrtowcs, mbsrtowcs_l, mbsnrtowcs, mbsnrtowcs_l - convert a character string to a wide-character string (restartable)

LIBRARY
libc

SYNOPSIS
#include <wchar.h>
size_t
mbsrtowcs(wchar_t * restrict dst, const char ** restrict src, size_t len, mbstate_t * restrict ps);
size_t
mbsnrtowcs(wchar_t * restrict dst, const char ** restrict src, size_t nms, size_t len, mbstate_t * restrict ps);
#include <xlocale.h>
size_t
mbsrtowcs_l(wchar_t * restrict dst, const char ** restrict src, size_t len, mbstate_t * restrict ps, locale_t locale);
size_t
mbsnrtowcs_l(wchar_t * restrict dst, const char ** restrict src, size_t nms, size_t len, mbstate_t * restrict ps, locale_t locale);

DESCRIPTION
The mbsrtowcs() and mbsrtowcs_l() functions convert a sequence of multibyte characters pointed to indirectly by src into a sequence of corresponding wide characters and store at most len of them in the wchar_t array pointed to by dst, until they encounter a terminating null character ('\0').

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, mbsrtowcs() and mbsrtowcs_l() use an internal, static mbstate_t object, which is initialized to the initial conversion state at program startup.

The mbsnrtowcs() and mbsnrtowcs_l() functions behave identically to mbsrtowcs() and mbsrtowcs_l(), except that conversion stops after reading at most nms bytes from the buffer pointed to by src.

The mbsrtowcs_l() and mbsnrtowcs_l() functions take an explicit locale argument, whereas the mbsrtowcs() and mbsnrtowcs() functions use the current global or per-thread locale.

RETURN VALUES
The mbsrtowcs(), mbsrtowcs_l(), mbsnrtowcs(), and mbsnrtowcs_l() functions return the number of wide characters stored in the array pointed to by dst if successful, otherwise they return (size_t)-1.

ERRORS
The mbsrtowcs(), mbsrtowcs_l(), mbsnrtowcs(), and mbsnrtowcs_l() functions will fail if:

[EILSEQ]
    An invalid multibyte character sequence was encountered.

[EINVAL]
    The conversion state is invalid.

SEE ALSO
mbrtowc(3), mbstowcs(3), multibyte(3), wcsrtombs(3), xlocale(3)

STANDARDS
The mbsrtowcs() function conforms to isoC-99.

The mbsrtowcs_l(), mbsnrtowcs(), and mbsnrtowcs_l() functions are an extension to the standard.