C++ <cstring> - memmove() Function

The C++ <cstring> memmove() function is used to copy num characters of memory block pointed to by source to the memory block pointed to by destination.

This method can be used even when the two memory blocks overlap. This is because copying takes place as if an intermediate buffer is created where the data are first copied to from source and then finally copied to destination.

The behavior of the function is undefined if either destination or source is a null pointer.

Syntax

void * memmove ( void * destination, const void * source, size_t num );

Parameters

Return Value

Returns destination

Example:

The example below shows the usage of memmove() function.

#include <iostream>
#include <cstring>
using namespace std;
 
int main (){
  char str[50] = "1234567890";

  //displaying content of str
  cout<<"str contains: "<<str<<"\n";

  //copying first 5 characters of str
  memmove(str + 5, str, 5);

  //displaying the result
  cout<<"str contains: "<<str;

  return 0;
}

The output of the above code will be:

str contains: 1234567890
str contains: 1234512345