1 /* strncmp -- compare two strings, stop after n bytes.
2 This function is in the public domain. */
3
4 /*
5
6 @deftypefn Supplemental int strncmp (const char *@var{s1}, @
7 const char *@var{s2}, size_t @var{n})
8
9 Compares the first @var{n} bytes of two strings, returning a value as
10 @code{strcmp}.
11
12 @end deftypefn
13
14 */
15
16 #include <ansidecl.h>
17 #include <stddef.h>
18
19 int
strncmp(const char * s1,const char * s2,register size_t n)20 strncmp(const char *s1, const char *s2, register size_t n)
21 {
22 register unsigned char u1, u2;
23
24 while (n-- > 0)
25 {
26 u1 = (unsigned char) *s1++;
27 u2 = (unsigned char) *s2++;
28 if (u1 != u2)
29 return u1 - u2;
30 if (u1 == '\0')
31 return 0;
32 }
33 return 0;
34 }
35