Synopsis
#include <stdlib.h>
int wctomb(char *str, wchar_t wchar);
Status
Declared, not implemented
Conformance
IEEE Std 1003.1-2017
Description
The wctomb() function shall determine the number of bytes needed to represent the character corresponding to the
wide-character code whose value is wchar (including any change in the shift state). It shall store the character
representation (possibly multiple bytes and any special bytes to change shift state) in the array object pointed to
by s (if s is not a null pointer). At most MB_CUR_MAX bytes shall be stored. If wchar is 0, a null byte
shall be stored, preceded by any shift sequence needed to restore the initial shift state, and wctomb() shall be
left in the initial shift state.
The behavior of this function is affected by the LC_CTYPE category of the current locale. For a state-dependent
encoding, this function shall be placed into its initial state by a call for which its character pointer
argument, s, is a null pointer. Subsequent calls with s as other than a null pointer shall cause the internal
state of the function to be altered as necessary. A call with s as a null pointer shall cause this function to
return a non-zero value if encodings have state dependency, and 0 otherwise. Changing the LC_CTYPE category causes
the shift state of this function to be unspecified.
The wctomb() function need not be thread-safe.
The implementation shall behave as if no function defined in this volume of POSIX.1-2017 calls wctomb().
Return value
If s is a null pointer, wctomb() shall return a non-zero or 0 value, if character encodings, respectively, do or
do not have state-dependent encodings. If s is not a null pointer, wctomb() shall return -1 if the value of
wchar does not correspond to a valid character, or return the number of bytes that constitute the character
corresponding to the value of wchar.
In no case shall the value returned be greater than the value of the MB_CUR_MAX macro.
Errors
The wctomb() function shall fail if:
EILSEQAn invalid wide-character code is detected.
Tests
Untested
Known bugs
None