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”).