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

54 lines
1.4 KiB
C

/*
FUNCTION
<<wcsncpy>>---copy part of a wide-character string
SYNOPSIS
#include <wchar.h>
wchar_t *wcsncpy(wchar_t *__restrict <[s1]>,
const wchar_t *__restrict <[s2]>, size_t <[n]>);
DESCRIPTION
The <<wcsncpy>> 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. Note that if <[s1]> contains more than <[n]>
wide characters before its terminating null, the result is not
null-terminated.
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 <<wcsncpy>> function returns <[s1]>; no return value is reserved to
indicate an error.
PORTABILITY
ISO/IEC 9899; POSIX.1.
No supporting OS subroutines are required.
*/
#include <_ansi.h>
#include <wchar.h>
wchar_t *
_DEFUN (wcsncpy, (s1, s2, n),
wchar_t *__restrict s1 _AND
_CONST wchar_t *__restrict s2 _AND
size_t n)
{
wchar_t *dscan=s1;
while(n > 0)
{
--n;
if((*dscan++ = *s2++) == L'\0') break;
}
while(n-- > 0) *dscan++ = L'\0';
return s1;
}