MBSTOWCS(3) | Library Functions Manual | MBSTOWCS(3)

# 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”).

March 16, 2011 | NetBSD 9.5