NAME

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

LIBRARY

Standard C Library (libc, -lc)

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), wcstombs(3)

STANDARDS

The mbstowcs() function conforms to ANSI X3.159-1989 (“ANSI C89”). The restrict qualifier is added at ISO/IEC 9899:1999 (“ISO C99”).