C Standard Library

C <string.h> - memcpy() Function

The C <string.h> memcpy() function is used to copy num characters of memory block pointed to by source to the memory block pointed to by destination. The behavior of the function is undefined if:

destination and source overlaps.
either destination or source is a null pointer.

Syntax

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

Parameters

`destination`	Specify pointer to the first block of memory where the content is to be copied.
`source`	Specify pointer to the second block of memory to copy from.
`num`	Specify number of characters to copy. size_t is an unsigned integer type.

Return Value

Returns destination

Example:

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

#include <stdio.h>
#include <string.h>
 
int main (){
  char str[50] = "Hello World!";
  char new_str[50];
  
  //copying 5 characters of memory 
  //blocks str into memory block new_str
  memcpy(new_str, str, 5);

  //displaying the result
  printf("new_str contains: %s", new_str);

  return 0;
}

The output of the above code will be:

new_str contains: Hello

❮ C <string.h> Library