Malloc() function, dynamic allocation, returns a pointer to the first byte of memory location of the specified "size" allocated from the heap. If there is no sufficient space the function returns a "NULL" pointer. It performs Dynamic Memory Allocation at run time.

    void *malloc(size_t size);   

#include <stdlib.h>
#include <stdio.h>
int main ()
 {
    int * ptr;
    ptr = (int*) malloc (80*sizeof(int));
    if( ptr== NULL )
      {printf( "Insufficient memory\n" );}
    else
      {printf( "Memory block allocated\n" );} 
    return(0);
 }

   Memory block allocated

In the above example, first the memory is allocated, then its checked using a "if" loop. Thus to allocate memory block this function can be used. This is the malloc() function of dynamic allocation.