MBSTOWCS(3)

NAME
mbstowcs - converts a multibyte character string to a wide-character string

LIBRARY
libc

SYNOPSIS
#include <stdlib.h>
size_t
mbstowcs(wchar_t * restrict pwcs, const char * restrict s, size_t n);

DESCRIPTION
mbstowcs() converts a nul-terminated multibyte character string pointed to by s to the corresponding wide-character string and stores it in the array pointed to by pwcs. This function may modify the first at most n elements of the array pointed to by pwcs. Each character will be converted as if mbtowc(3) is continuously called, except the internal state of mbtowc(3) will not be affected.

For state-dependent encoding, mbstowcs() implies the multibyte character string pointed to by s always begins with an initial state.

These are the special cases:

pwcs == NULL
    mbstowcs() returns the number of elements to store the whole wide-character string corresponding to the multibyte character string pointed to by s. In this case, n is ignored.

s == NULL
    Undefined (may cause the program to crash).

RETURN VALUES
mbstowcs() returns:

0 or positive
    Number of elements stored in the array pointed to by pwcs. There are no cases that the value returned is greater than n (unless pwcs is a null pointer) or the value of the MB_CUR_MAX macro. If the return value is equal to n, the string pointed to by pwcs will not be nul-terminated.

(size_t)-1
    s points to a string containing an invalid or incomplete multibyte character. The mbstowcs() also sets errno to indicate the error.

ERRORS
mbstowcs() may cause an error in the following case:

[EILSEQ]
    s points to a string containing an invalid or incomplete multibyte character.

SEE ALSO
mbtowc(3), setlocale(3)

STANDARDS
The mbstowcs() function conforms to ansiC. The restrict qualifier is added at isoC-99.