C library function - memmove()

Description

The C library function void *memmove(void *str1, const void *str2, size_t n) copies n characters from str2 to str1, but for overlapping memory blocks, memmove() is a safer approach than memcpy().

Declaration

Following is the declaration for memmove() function.

void *memmove(void *str1, const void *str2, size_t n)

Parameters

• str1 − This is a pointer to the destination array where the content is to be copied, type-casted to a pointer of type void*.

• str2 − This is a pointer to the source of data to be copied, type-casted to a pointer of type void*.

• n − This is the number of bytes to be copied.

Return Value

This function returns a pointer to the destination, which is str1.

Example

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

#include <stdio.h>
#include <string.h>

int main () {
   char dest[] = "oldstring";
   const char src[]  = "newstring";

   printf("Before memmove dest = %s, src = %s\n", dest, src);
   memmove(dest, src, 9);
   printf("After memmove dest = %s, src = %s\n", dest, src);

   return(0);
}

Let us compile and run the above program that will produce the following result −

Before memmove dest = oldstring, src = newstring
After memmove dest = newstring, src = newstring