memcmp function

C

Function

Reference manual

@see man memcmp

The memcmp function compares two blocks of memory. It compares the first n bytes of the memory areas pointed to by ptr1 and ptr2.

Syntax

int memcmp(const void *ptr1, const void *ptr2, size_t n);

Parameters

• ptr1: A pointer to the first memory area to be compared.
• ptr2: A pointer to the second memory area to be compared.
• n: The number of bytes to be compared.

Return value

Returns an integer value less than, equal to, or greater than zero, depending on whether the first differing byte in ptr1 is less than, equal to, or greater than the corresponding byte in ptr2.

Example

In the following example we use the memcmp function to compare the strings “Hello” and “Helxo”, then we will print a message if they are equal, that is if the return value is 0, or a different message if they are different.

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

int main(void) {
    const char str1[] = "Hello";
    const char str2[] = "Helxo";
    int result = memcmp(str1, str2, 5);

    if (result == 0)
        printf("Strings are equal.\n");
    else
        printf("Strings are not equal.\n");
    return (0);
}