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memcmp, wmemcmp

Visual Studio .NET 2003

Compare characters in two buffers.

int memcmp(
   const void *buf1,
   const void *buf2,
   size_t count
);
int wmemcmp(
   const wchar_t * buf1,
   const wchar_t * buf2,
   size_t count
);

Parameters

buf1: First buffer.
buf2: Second buffer.
count: Number of bytes.

Return Value

The return value indicates the relationship between the buffers.

Return value	Relationship of first count bytes of buf1 and buf2
< 0	buf1 less than buf2
0	buf1 identical to buf2
> 0	buf1 greater than buf2

Remarks

Compares the first count bytes of buf1 and buf2 and returns a value indicating their relationship.

Requirements

Routine	Required header	Compatibility
memcmp	<memory.h> or <string.h>	ANSI, Win 98, Win Me, Win NT, Win 2000, Win XP
wmemcmp	<wchar.t>	ANSI, Win 98, Win Me, Win NT, Win 2000, Win XP

For additional compatibility information, see Compatibility in the Introduction.

Libraries

All versions of the C run-time libraries.

Example

// crt_memcmp.c
/* This program uses memcmp to compare
 * the strings named first and second. If the first
 * 19 bytes of the strings are equal, the program
 * considers the strings to be equal.
 */

#include <string.h>
#include <stdio.h>

int main( void )
{
   char first[]  = "12345678901234567890";
   char second[] = "12345678901234567891";
   int int_arr1[] = {1,2,3,4};
   int int_arr2[] = {1,2,3,4};
   int result;

   printf( "Compare '%.19s' to '%.19s':\n", first, second );
   result = memcmp( first, second, 19 );
   if( result < 0 )
      printf( "First is less than second.\n" );
   else if( result == 0 )
      printf( "First is equal to second.\n" );
   else
      printf( "First is greater than second.\n" );

   printf( "Compare '%d,%d' to '%d,%d':\n", int_arr1[0], int_arr1[1], int_arr2[0], int_arr2[1]);
   result = memcmp( int_arr1, int_arr2, sizeof(int) * 2 );
   if( result < 0 )
      printf( "int_arr1 is less than int_arr2.\n" );
   else if( result == 0 )
      printf( "int_arr1 is equal to int_arr2.\n" );
   else 
      printf( "int_arr1 is greater than int_arr2.\n" );
}

Output

Compare '1234567890123456789' to '1234567890123456789':
First is equal to second.
Compare '1,2' to '1,2':
int_arr1 is equal to int_arr2.