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WCTOMB(3) Library Functions Manual WCTOMB(3)

wctombconverts a wide character to a multibyte character

#include <stdlib.h>

wctomb(char * s, wchar_t wchar);

The () function converts the wide character wchar to the corresponding multibyte character, and stores it in the array pointed to by s. wctomb() may store at most MB_CUR_MAX bytes in the array.

In state-dependent encoding, () may store the special sequence to change the conversion state before an actual multibyte character into the array pointed to by s. If wchar is a null wide character (‘\0’), this function places its own internal state to an initial conversion state.

Calling any other functions in never change the internal state of (), except for calling setlocale(3) with the LC_CTYPE category changed to that of the current locale. Such setlocale(3) calls cause the internal state of this function to be indeterminate.

The behaviour of () is affected by LC_CTYPE category of the current locale.

There is a special case:

s == NULL
() initializes its own internal state to an initial state, and determines whether the current encoding is state-dependent. This function returns 0 if the encoding is state-independent, otherwise non-zero. In this case, wchar is completely ignored.

Normally, wctomb() returns:

Number of bytes for the valid multibyte character pointed to by s. There are no cases where the value returned is greater than the value of the MB_CUR_MAX macro.
wchar is an invalid wide character.

If s is equal to NULL, wctomb() returns:

The current encoding is state-independent.
The current encoding is state-dependent.

No errors are defined.


The wctomb() function conforms to ANSI X3.159-1989 (“ANSI C89”).

March 29, 2022 OpenBSD-7.2