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  null  wide  character
          ('\0').   In  this  case the number of wide characters written to dest, excluding the terminating null
          wide character, is returned.

       The programmer must ensure that there is room for at least n wide characters 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 memory, 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

       C99.

NOTES

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

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

SEE ALSO

       mbsrtowcs(3), wcstombs(3)

COLOPHON

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       information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.