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