memcpy in device, what if size = 0?

Accelerated Computing Teaching and Curriculum Support
1

I find that in memcpy, if the size = 0, the program will still copy one byte to destination. Why?

#include <iostream>
#include "cuda.h"
#include "cuda_runtime.h"
#include "device_functions.h"
using namespace std;
__global__ void copy(char *dev)
{
	char temp = 'g';
	memcpy(dev + 10,&temp,0);
}
int main( )
{
	char *host = new char [32];
	char *host1 = new char [32];
	char *dev;
	host = "abbbbbbbbbbbbbbbbbbbbbbbbbbb";
	cudaError error1 = cudaMalloc(&dev,32);
	cudaError error2 = cudaMemcpy(dev,host,32,cudaMemcpyHostToDevice);
	copy<<<1,1>>>(dev);
	cudaError error3 = cudaMemcpy(host1,dev,32,cudaMemcpyDeviceToHost);
	cout<<host1<<endl;
	return 0;
}