calloc() - allocate clean memory (zero initialized space)
#include <stdlib.h>
void * calloc (size_t nmemb, size_t size)
The calloc(3) function allocates space for an array of nmemb objects, each of whose size is size. The space is initialized to all bits zero.
The calloc(3) function returns a pointer to the allocated space if successful; otherwise it returns NULL.
free(3)
malloc(3)
realloc(3)