---
title: memcpy
description: "从源内存中拷贝指定长度字节数的数据至目标内存中。"
url: https://www.hikunpeng.com/document/detail/zh/kunpengboostkithistory/2300/accel/kunpengaccel_ksl_16_0024.html
sourcePath: /source/zh/kunpengboostkithistory/2300/accel/kunpengaccel_ksl_16_0024.html
indexId: 6e610e1a9dc4ae1ebf61b9148d44673b14b053102693020d893b12731ebada2674
---
# memcpy

从源内存中拷贝指定长度字节数的数据至目标内存中。

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

#### 参数

| 参数名 | 描述 | 取值范围 | 输入/输出 |
| --- | --- | --- | --- |
| destination | 指向用于存储复制内容的目标内存指针。 | 非空 | 输出 |
| source | 指向要复制的数据源内存指针。 | 非空 | 输入 |
| size | 被复制的字节数。 | 非负数 | 输入 |


#### 返回值

- 成功：返回指向目标存储区内存的指针。
- 失败：返回空指针。


#### 示例

```
#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;
}
```

运行结果：

```
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
```