strcmp

strcmp

Compare Two Null-Terminated Strings

Portability: ISO/ANSI C conforming, UNIX compatible

SYNOPSIS
DESCRIPTION
RETURN VALUE
CAUTION
IMPLEMENTATION
EXAMPLE
RELATED FUNCTIONS
SEE ALSO

SYNOPSIS

#include <string.h>

int strcmp(const char *str1, const char *str2);

DESCRIPTION

strcmp compares two character strings ( str1 and str2 ) using the standard EBCDIC collating sequence. The return value has the same relationship to 0 as str1 has to str2 . If two strings are equal up to the point at which one terminates (that is, contains a null character), the longer string is considered greater.

RETURN VALUE

The return value from strcmp is 0 if the two strings are equal, less than 0 if str1 compares less than str2 , and greater than 0 if str1 compares greater than str2 . No other assumptions should be made about the value returned by strcmp .

CAUTION

If one of the arguments of strcmp is not properly terminated, a protection or addressing exception may occur. If one of the arguments to the built-in version of strcmp is a constant, the compiler generates a CLC instruction to perform the entire comparison. If the variable argument is not null terminated, the character-by-character comparison may perform as expected, but a comparison by the CLC instruction may cause an addressing exception in rare cases.

IMPLEMENTATION

The compiler generates inline code for strcmp unless strcmp is undefined (by an #undef statement) to prevent this. The inline code may still call a library routine in special cases.

EXAMPLE

#include <lcstring.h>
#include <stdio.h>
#include <stdlib.h>

main()
{
   char command[20];
   int n = 0;

   for(;;) {
      ++n;
      printf("Enter command # %d\n", n);
      puts("Enter quit to terminate/any other command to continue");
      gets(command_;
      if (strcmp(command, "quit") == 0) break;

         /* Determine whether command is equal to quit. */
      strlwr(command);
      if (strcmp(command, "quit") == 0)
         exit(0);
      puts("Did you meant to say quit? (Case is significant.)");
   }
}

RELATED FUNCTIONS

memcmp , strcoll , strncmp , strxfrm

SEE ALSO

String Utility Functions

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