mbstowcs

MBSTOWCS(3)                Linux Programmer's Manual               MBSTOWCS(3)



NAME
       mbstowcs - convert a multibyte string to a wide character string

SYNOPSIS
       #include <stdlib.h>

       size_t mbstowcs(wchar_t *dest, const char *src, size_t n);

DESCRIPTION
       If  dest  is  not  a  NULL  pointer, the mbstowcs function converts the
       multibyte string src to a wide-character string starting at  dest.   At
       most  n  wide  characters are written to dest. The conversion starts in
       the initial state. The conversion can stop for three reasons:

       1. An invalid multibyte sequence has been  encountered.  In  this  case
       (size_t)(-1) is returned.

       2.  n  non-L'\0' wide characters have been stored at dest. In this case
       the number of wide characters written to  dest  is  returned,  but  the
       shift state at this point is lost.

       3.  The  multibyte  string has been completely converted, including the
       terminating '\0'. In this case the number of wide characters written to
       dest, excluding the terminating L'\0' character, is returned.

       The programmer must ensure that there is room for at least n wide char-
       acters at dest.

       If dest is NULL, n is ignored, and the conversion  proceeds  as  above,
       except  that  the converted wide characters are not written out to mem-
       ory, and that no length limit exists.

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

RETURN VALUE
       The  mbstowcs  function returns the number of wide characters that make
       up the converted part of the wide character string, not  including  the
       terminating  null  wide character. If an invalid multibyte sequence was
       encountered, (size_t)(-1) is returned.

CONFORMING TO
       ISO/ANSI C, UNIX98

SEE ALSO
       mbsrtowcs(3)

NOTES
       The behaviour of mbstowcs depends on the LC_CTYPE category of the  cur-
       rent locale.

       The  function  mbsrtowcs  provides a better interface to the same func-
       tionality.



GNU                               1999-07-25                       MBSTOWCS(3)