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mbtowc
Converts a single multibyte character to its wide character
representation.
Syntax
#include <stdlib.h>
int mbtowc(wchar_t *pwc, const char *s,size_t n);
Parameters
pwc A pointer to an object of type wchar_t to which the
function returns the converted value.
s A pointer to a multibyte character to be converted.
n An expression of type size_t indicating the number of
characters in s to be examined. This should be no greater
than the value of MB_CUR_MAX.
Return Values
>0 The number of bytes that are in the converted multibyte
character.
-1 The s parameter does not point to a valid multibyte
character.
0 The s parameter is a null pointer and multibyte character
encodings are not state-dependent, or s points to a null
character.
Description
If s is not a null pointer, mbtowc determines the number of bytes in the
multibyte character pointed to by s. It then determines the code for the
value of type wchar_t that corresponds to that multibyte character. (The
value of the code corresponding to the null character is zero.)
If the multibyte character is valid and pwc is not a null pointer, mbtowc
stores the code in the object pointed to by pwc. A maximum of n
characters are examined, starting at the character pointed to by s.
This function retains state information. Multibyte encodings can be
state-dependent, employing "shift characters" to alter the meaning of
subsequent characters. The shift state is persistent between calls to
the routines for processing extended character sets unless the LC_CTYPE
category of the locale is changed.
Calling this function with the s argument set to NULL resets the function
to its initial state. When using a NULL pointer to clear the shift
state, zero is returned if the multibyte shift state was previously
clear. A nonzero value is returned if the locale-specific shift state
was previously set.
See Also
wchar_t, MB_CUR_MAX, wctomb(), mbstowcs(), wcstombs(), ANSI C 4.10.7.2