memcpy

Copy data of a specified length from the source memory to the destination memory.

void *memcpy(void * destination, const void *source, size_t size);

Parameters

Parameter	Description	Value Range	Input/Output
destination	Pointer to the destination memory used to store the copied data.	The value cannot be NULL.	Output
source	Pointer to the source memory from which data is to be copied.	The value cannot be NULL.	Input
size	Number of copied bytes.	The value cannot be negative.	Input

Return Value

Success: A pointer to the destination memory is returned.
Failure: A null pointer is returned.

Example

#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <string.h>
#include "kqmalloc.h"

#define KQMALLOC_TEST_LEN 10

void MemcpyExample()
{
    int8_t *source = (int8_t *)malloc(KQMALLOC_TEST_LEN * sizeof(int8_t));
    if (source == NULL) {
        printf("source is null\n");
        return;
    } else {
        printf("source address: %lx\n", source);
        for (int8_t i = 0; i < KQMALLOC_TEST_LEN; ++i) {
            source[i] = i;
        }
        printf("source test data:");
        for (int8_t i = 0; i < KQMALLOC_TEST_LEN; ++i) {
            printf(" %d", source[i]);
        }
        printf("\n");
    }

    int8_t *destination = (int8_t *)malloc(KQMALLOC_TEST_LEN * sizeof(int8_t));
    if (destination == NULL) {
        printf("destination is null\n");
        free(source);
        return;
    } else {
        printf("destination address: %lx\n", destination);
        printf("destination test data before memcpy:");
        for (int8_t i = 0; i < KQMALLOC_TEST_LEN; ++i) {
            printf(" %d", destination[i]);
        }
        printf("\n");
    }
    int8_t *res = memcpy(destination , source, KQMALLOC_TEST_LEN * sizeof(int8_t));
    printf("res address: %lx\n", res);
    if (res != NULL) {
        printf("res test data after memcpy:");
        for (int8_t i = 0; i < KQMALLOC_TEST_LEN; ++i) {
            printf(" %d", res[i]);
        }
        printf("\n");
    }

    free(source);
    free(destination);
}

int main(void) {
    MemcpyExample();
    return 0;
}

Output:

source address: ffffbb202174
source test data: 0 1 2 3 4 5 6 7 8 9
destination address: ffffbb202168
destination test data before memcpy: 92 33 32 -69 -1 -1 0 0 0 0
res address: ffffbb202168
res test data after memcpy: 0 1 2 3 4 5 6 7 8 9

Parent topic: Function Syntax