NAME

       mbstowcs - convert a multibyte string to a wide character string

SYNOPSIS

       #include <stdlib.h>

       size_t mbstowcs (wchar_t *dest, const char *src, size_t n);

DESCRIPTION

       If  dest is not a NULL pointer, the mbstowcs function converts the multibyte string src to
       a wide-character string starting at dest.  At most n wide characters are written to  dest.
       The conversion starts in the initial state. The conversion can stop for three reasons:

       1.  An  invalid  multibyte  sequence  has  been  encountered. In this case (size_t)(-1) is
       returned.

       2. n non-L'\0' wide characters have been stored at dest. In this case the number  of  wide
       characters written to dest is returned, but the shift state at this point is lost.

       3.  The multibyte string has been completely converted, including the terminating '\0'. In
       this case the number of wide characters written to dest, excluding the  terminating  L'\0'
       character, is returned.

       The programmer must ensure that there is room for at least n wide characters at dest.

       If  dest  is  NULL,  n  is  ignored, and the conversion proceeds as above, except that the
       converted wide characters are not written out to memory, and that no length limit exists.

       In order to avoid the case 2 above, the programmer should make sure n is greater or  equal
       to mbstowcs(NULL,src,0)+1.

RETURN VALUE

       The  mbstowcs  function  returns  the number of wide characters that make up the converted
       part of the wide character string, not including the terminating null wide  character.  If
       an invalid multibyte sequence was encountered, (size_t)(-1) is returned.

CONFORMING TO

       ISO/ANSI C, UNIX98

SEE ALSO

       mbsrtowcs(3)

NOTES

       The behaviour of mbstowcs depends on the LC_CTYPE category of the current locale.

       The function mbsrtowcs provides a better interface to the same functionality.