Frees a previously allocated memory block.
#include <stdlib.h>
void free (
void *ptr);
(IN) Points to a memory block previously allocated by a call to calloc, malloc, or realloc.
When the value of ptr is NULL, the free function does nothing; otherwise, the free function deallocates the memory block located by the ptr parameter.
After a call to free, the freed memory block is available for allocation.