Compare characters in two buffers.
int memcmp( const void *buf1, const void *buf2, size_t count );
| Routine | Required Header | Compatibility |
| memcmp | <memory.h> or <string.h> | ANSI, Win 95, Win NT |
For additional compatibility information, see Compatibility in the Introduction.
Libraries
| LIBC.LIB | Single thread static library, retail version |
| LIBCMT.LIB | Multithread static library, retail version |
| MSVCRT.LIB | Import library for MSVCRT.DLL, retail version |
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 |
Parameters
buf1
First buffer
buf2
Second buffer
count
Number of characters
Remarks
The memcmp function compares the first count bytes of buf1 and buf2 and returns a value indicating their relationship.
Example
/* 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>
void main( void )
{
char first[] = "12345678901234567890";
char second[] = "12345678901234567891";
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 if( result > 0 )
printf( "First is greater than second.\n" );
printf( "Compare '%.20s' to '%.20s':\n", first, second );
result = memcmp( first, second, 20 );
if( result < 0 )
printf( "First is less than second.\n" );
else if( result == 0 )
printf( "First is equal to second.\n" );
else if( result > 0 )
printf( "First is greater than second.\n" );
}
Output
Compare '1234567890123456789' to '1234567890123456789':
First is equal to second.
Compare '12345678901234567890' to '12345678901234567891':
First is less than second.