NAME

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

LIBRARY

       Standard C library (libc, -lc)

SYNOPSIS

       #include <stdlib.h>

       size_t wcstombs(char dest[restrict .n], const wchar_t *restrict src,
                       size_t n);

DESCRIPTION

       If  dest  is not NULL, the wcstombs() function converts the wide-character string src to a
       multibyte string starting at dest.  At most n bytes are written to dest.  The sequence  of
       characters  placed in dest begins in the initial shift state.  The conversion can stop for
       three reasons:

       •  A wide character has been encountered that  can  not  be  represented  as  a  multibyte
          sequence (according to the current locale).  In this case, (size_t) -1 is returned.

       •  The  length  limit forces a stop.  In this case, the number of bytes written to dest is
          returned, but the shift state at this point is lost.

       •  The wide-character string has been completely converted, including the terminating null
          wide  character (L'\0').  In this case, the conversion ends in the initial shift state.
          The number of bytes written to dest, excluding the terminating  null  byte  ('\0'),  is
          returned.

       The programmer must ensure that there is room for at least n bytes at dest.

       If  dest  is  NULL,  n  is  ignored, and the conversion proceeds as above, except that the
       converted bytes are not written out to memory, and no length limit exists.

       In order to avoid the case 2 above, the programmer should make sure n is greater  than  or
       equal to wcstombs(NULL,src,0)+1.

RETURN VALUE

       The  wcstombs()  function returns the number of bytes that make up the converted part of a
       multibyte sequence, not including the terminating null byte.   If  a  wide  character  was
       encountered which could not be converted, (size_t) -1 is returned.

ATTRIBUTES

       For an explanation of the terms used in this section, see attributes(7).

       ┌───────────────────────────────────────────────────────────────┬───────────────┬─────────┐
       │Interface                                                      │ Attribute     │ Value   │
       ├───────────────────────────────────────────────────────────────┼───────────────┼─────────┤
       │wcstombs()                                                     │ Thread safety │ MT-Safe │
       └───────────────────────────────────────────────────────────────┴───────────────┴─────────┘

VERSIONS

       The function wcsrtombs(3) provides a better interface to the same functionality.

STANDARDS

       C11, POSIX.1-2008.

HISTORY

       POSIX.1-2001, C99.

NOTES

       The behavior of wcstombs() depends on the LC_CTYPE category of the current locale.

SEE ALSO

       mblen(3), mbstowcs(3), mbtowc(3), wcsrtombs(3), wctomb(3)