/*FUNCTION	<<strcmp>>---character string compare	INDEX	strcmp SYNOPSIS	#include <string.h>	int strcmp(const char *<[a]>, const char *<[b]>); DESCRIPTION	<<strcmp>> compares the string at <[a]> to	the string at <[b]>. RETURNS	If <<*<[a]>>> sorts lexicographically after <<*<[b]>>>,	<<strcmp>> returns a number greater than zero.  If the two	strings match, <<strcmp>> returns zero.  If <<*<[a]>>>	sorts lexicographically before <<*<[b]>>>, <<strcmp>> returns a	number less than zero. PORTABILITY<<strcmp>> is ANSI C. <<strcmp>> requires no supporting OS subroutines. QUICKREF	strcmp ansi pure*/ #include <string.h>#include <limits.h>#include "local.h" intstrcmp (const char *s1,	const char *s2){ #if defined(PREFER_SIZE_OVER_SPEED) || defined(__OPTIMIZE_SIZE__)  while (*s1 != '\0' && *s1 == *s2)    {      s1++;      s2++;    }   return (*(unsigned char *) s1) - (*(unsigned char *) s2);#else  unsigned long *a1;  unsigned long *a2;   /* If s1 or s2 are unaligned, then compare bytes. */  if (!UNALIGNED_X_Y(s1, s2))    {        /* If s1 and s2 are word-aligned, compare them a word at a time. */      a1 = (unsigned long*)s1;      a2 = (unsigned long*)s2;      while (*a1 == *a2)        {          /* To get here, *a1 == *a2, thus if we find a null in *a1,	     then the strings must be equal, so return zero.  */          if (DETECT_NULL(*a1))	    return 0;           a1++;          a2++;        }       /* A difference was detected in last few bytes of s1, so search bytewise */      s1 = (char*)a1;      s2 = (char*)a2;    }   while (*s1 != '\0' && *s1 == *s2)    {      s1++;      s2++;    }  return (*(unsigned char *) s1) - (*(unsigned char *) s2);#endif /* not PREFER_SIZE_OVER_SPEED */}