wcstombs man page

Prolog

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wcstombs — convert a wide-character string to a character string

Synopsis

#include <stdlib.h>

size_t wcstombs(char *restrict s, const wchar_t *restrict pwcs,
    size_t n);

Description

The functionality described on this reference page is aligned with the ISO C standard. Any conflict between the requirements described here and the ISO C standard is unintentional. This volume of POSIX.1‐2008 defers to the ISO C standard.

The wcstombs() function shall convert the sequence of wide-character codes that are in the array pointed to by pwcs into a sequence of characters that begins in the initial shift state and store these characters into the array pointed to by s, stopping if a character would exceed the limit of n total bytes or if a null byte is stored. Each wide-character code shall be converted as if by a call to wctomb(), except that the shift state of wctomb() shall not be affected.

The behavior of this function shall be affected by the LC_CTYPE category of the current locale.

No more than n bytes shall be modified in the array pointed to by s. If copying takes place between objects that overlap, the behavior is undefined. If s is a null pointer, wcstombs() shall return the length required to convert the entire array regardless of the value of n, but no values are stored.

Return Value

If a wide-character code is encountered that does not correspond to a valid character (of one or more bytes each), wcstombs() shall return (size_t)-1. Otherwise, wcstombs() shall return the number of bytes stored in the character array, not including any terminating null byte. The array shall not be null-terminated if the value returned is n.

Errors

The wcstombs() function shall fail if:

EILSEQ
A wide-character code does not correspond to a valid character.

The following sections are informative.

See Also

mblen(), mbtowc(), mbstowcs(), wctomb()

The Base Definitions volume of POSIX.1‐2008, <stdlib.h>

Info

2013 IEEE/The Open Group POSIX Programmer's Manual