memcmp.c revision 302408 
1/* memcmp -- compare two memory regions.
2   This function is in the public domain.  */
3
4/*
5
6@deftypefn Supplemental int memcmp (const void *@var{x}, const void *@var{y}, size_t @var{count})
7
8Compares the first @var{count} bytes of two areas of memory.  Returns
9zero if they are the same, a value less than zero if @var{x} is
10lexically less than @var{y}, or a value greater than zero if @var{x}
11is lexically greater than @var{y}.  Note that lexical order is determined
12as if comparing unsigned char arrays.
13
14@end deftypefn
15
16*/
17
18#include <ansidecl.h>
19#include <stddef.h>
20
21int
22memcmp (const PTR str1, const PTR str2, size_t count)
23{
24  register const unsigned char *s1 = (const unsigned char*)str1;
25  register const unsigned char *s2 = (const unsigned char*)str2;
26
27  while (count-- > 0)
28    {
29      if (*s1++ != *s2++)
30	  return s1[-1] < s2[-1] ? -1 : 1;
31    }
32  return 0;
33}
34
35