mbstowcs - convert a character string to a wide-character string
Library Synopsis Description Return Values Errors See Also Standards
.In stdlib.h size_t .Fo mbstowcs "wchar_t * restrict wcstring" "const char * restrict mbstring" "size_t nwchars" .Fc
The mbstowcs function converts a multibyte character string mbstring beginning in the initial conversion state into a wide character string wcstring. No more than nwchars wide characters are stored. A terminating null wide character is appended if there is room.
The mbstowcs function returns the number of wide characters converted, not counting any terminating null wide character, or -1 if an invalid multibyte character was encountered.
The mbstowcs function will fail if: