1 /*
2 FUNCTION
3 <<wcpncpy>>---copy part of a wide-character string returning a pointer to its end
4
5 SYNOPSIS
6 #include <wchar.h>
7 wchar_t *wcpncpy(wchar_t *__restrict <[s1]>,
8 const wchar_t *__restrict <[s2]>, size_t <[n]>);
9
10 DESCRIPTION
11 The <<wcpncpy>> function copies not more than n wide-character codes
12 (wide-character codes that follow a null wide-character code are not
13 copied) from the array pointed to by <[s2]> to the array pointed to
14 by <[s1]>. If copying takes place between objects that overlap, the
15 behaviour is undefined.
16
17 If the array pointed to by <[s2]> is a wide-character string that is
18 shorter than <[n]> wide-character codes, null wide-character codes are
19 appended to the copy in the array pointed to by <[s1]>, until <[n]>
20 wide-character codes in all are written.
21
22 RETURNS
23 The <<wcpncpy>> function returns <[s1]>; no return value is reserved to
24 indicate an error.
25
26 PORTABILITY
27 <<wcpncpy>> is ISO/IEC 9899/AMD1:1995 (ISO C).
28
29 No supporting OS subroutines are required.
30 */
31
32 #include <_ansi.h>
33 #include <wchar.h>
34
35 wchar_t *
wcpncpy(wchar_t * __restrict dst,const wchar_t * __restrict src,size_t count)36 wcpncpy (wchar_t *__restrict dst,
37 const wchar_t *__restrict src,
38 size_t count)
39 {
40 wchar_t *ret = NULL;
41
42 while (count > 0)
43 {
44 --count;
45 if ((*dst++ = *src++) == L'\0')
46 {
47 ret = dst - 1;
48 break;
49 }
50 }
51 while (count-- > 0)
52 *dst++ = L'\0';
53
54 return ret ? ret : dst;
55 }
56