The Single UNIX ® Specification, Version 2
Copyright © 1997 The Open Group


wcrtomb - convert a wide-character code to a character (restartable)


#include <stdio.h>

size_t wcrtomb(char *s, wchar_t wc, mbstate_t *ps);


If s is a null pointer, the wcrtomb() function is equivalent to the call:

wcrtomb(buf, L'\0', ps)

where buf is an internal buffer.

If s is not a null pointer, the wcrtomb() function determines the number of bytes needed to represent the character that corresponds to the wide-character given by wc (including any shift sequences), and stores the resulting bytes in the array whose first element is pointed to by s. At most MB_CUR_MAX bytes are stored. If wc is a null wide-character, a null byte is stored, preceded by any shift sequence needed to restore the initial shift state. The resulting state described is the initial conversion state.

If ps is a null pointer, the wcrtomb() function uses its own internal mbstate_t object, which is initialised at program startup to the initial conversion state. Otherwise, the mbstate_t object pointed to by ps is used to completely describe the current conversion state of the associated character sequence. The implementation will behave as if no function defined in this specification calls wcrtomb().

The behaviour of this function is affected by the LC_CTYPE category of the current locale.


The wcrtomb() function returns the number of bytes stored in the array object (including any shift sequences). When wc is not a valid wide-character, an encoding error occurs. In this case, the function stores the value of the macros EILSEQ in errno and returns (size_t)-1; the conversion state is undefined.


The wcrtomb() function may fail if:
ps points to an object that contains an invalid conversion state.
Invalid wide-character code is detected.








mbsinit(), <wchar.h>.


Derived from the ISO/IEC 9899:1990/Amendment 1:1995 (E).

UNIX ® is a registered Trademark of The Open Group.
Copyright © 1997 The Open Group
[ Main Index | XSH | XCU | XBD | XCURSES | XNS ]