sysdeps/generic/strcmp.c

   1 /* Copyright (C) 1991, 1996 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Library General Public License as
   6    published by the Free Software Foundation; either version 2 of the
   7    License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Library General Public License for more details.
  13
  14    You should have received a copy of the GNU Library General Public
  15    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  16    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  17    Boston, MA 02111-1307, USA.  */
  18
  19 #include <string.h>
  20 #include <memcopy.h>
  21
  22 /* Compare S1 and S2, returning less than, equal to or
  23    greater than zero if S1 is lexicographically less than,
  24    equal to or greater than S2.  */
  25 int
  26 strcmp (p1, p2)
  27      const char *p1;
  28      const char *p2;
  29 {
  30   register const unsigned char *s1 = (const unsigned char *) p1;
  31   register const unsigned char *s2 = (const unsigned char *) p2;
  32   unsigned reg_char c1, c2;
  33
  34   do
  35     {
  36       c1 = (unsigned char) *s1++;
  37       c2 = (unsigned char) *s2++;
  38       if (c1 == '\0')
  39         return c1 - c2;
  40     }
  41   while (c1 == c2);
  42
  43   return c1 - c2;
  44 }