wcstombs(3) — Linux manual page

wcstombs(3)             Library Functions Manual             wcstombs(3)

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)

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Linux man-pages 6.9.1          2024-06-15                    wcstombs(3)

Pages that refer to this page: MB_CUR_MAX(3), mbstowcs(3), mbtowc(3), wcsrtombs(3), wctomb(3), locale(7)

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