newlib-cygwin/newlib/libc/string/wcpncpy.c

62 lines
1.4 KiB
C

/*
FUNCTION
<<wcpncpy>>---copy part of a wide-character string returning a pointer to its end
ANSI_SYNOPSIS
#include <wchar.h>
wchar_t *wcpncpy(wchar_t *<[s1]>, const wchar_t *<[s2]>, size_t <[n]>);
TRAD_SYNOPSIS
wchar_t *wcpncpy(<[s1]>, <[s2]>, <[n]>
wchar_t *<[s1]>;
const wchar_t *<[s2]>;
size_t <[n]>;
DESCRIPTION
The <<wcpncpy>> function copies not more than n wide-character codes
(wide-character codes that follow a null wide-character code are not
copied) from the array pointed to by <[s2]> to the array pointed to
by <[s1]>. If copying takes place between objects that overlap, the
behaviour is undefined.
If the array pointed to by <[s2]> is a wide-character string that is
shorter than <[n]> wide-character codes, null wide-character codes are
appended to the copy in the array pointed to by <[s1]>, until <[n]>
wide-character codes in all are written.
RETURNS
The <<wcpncpy>> function returns <[s1]>; no return value is reserved to
indicate an error.
PORTABILITY
<<wcpncpy>> is ISO/IEC 9899/AMD1:1995 (ISO C).
No supporting OS subroutines are required.
*/
#include <_ansi.h>
#include <wchar.h>
wchar_t *
_DEFUN (wcpncpy, (dst, src, count),
wchar_t * dst _AND
_CONST wchar_t * src _AND
size_t count)
{
wchar_t *ret = NULL;
while (count > 0)
{
--count;
if ((*dst++ = *src++) == L'\0')
{
ret = dst - 1;
break;
}
}
while (count-- > 0)
*dst++ = L'\0';
return ret ? ret : dst;
}