sysdeps/generic/strcmp.c

   1 /* Copyright (C) 1991 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
  16 not, write to the Free Software Foundation, Inc., 675 Mass Ave,
  17 Cambridge, MA 02139, USA.  */
  18
  19 #include <ansidecl.h>
  20 #include <string.h>
  21 #include <memcopy.h>
  22
  23 /* Compare S1 and S2, returning less than, equal to or
  24    greater than zero if S1 is lexiographically less than,
  25    equal to or greater than S2.  */
  26 int
  27 DEFUN(strcmp, (p1, p2), CONST char *p1 AND CONST char *p2)
  28 {
  29   register CONST unsigned char *s1 = (CONST unsigned char *) p1;
  30   register CONST unsigned char *s2 = (CONST unsigned char *) p2;
  31   unsigned reg_char c1, c2;
  32
  33   do
  34     {
  35       c1 = (unsigned char) *s1++;
  36       c2 = (unsigned char) *s2++;
  37       if (c1 == '\0')
  38         return c1 - c2;
  39     }
  40   while (c1 == c2);
  41
  42   return c1 - c2;
  43 }