NAME
mbstowcs —
converts a multibyte character string
to a wide-character string
LIBRARY
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_MAXmacro. 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
STANDARDS
The mbstowcs() function conforms to
ANSI X3.159-1989 (“ANSI C89”).
The restrict qualifier is added at ISO/IEC 9899:1999
(“ISO C99”).