Also, do realize that it's a bug to attempt to use just a pointer to access memory unless the memory has already been allocated. Remember that pointers have no memory; they have to be allocated memory (either statically at compile time or dynamically at runtime).
For example, one writes a C function that uses the parameter as a return value—a common C programming trick (these are often called value-result or in-out parameters):
unsigned long *uptr; [...] my_awesome_func(uptr); // bug! value to be returned in 'uptr'[...]
This is a bug; the uptr variable is just a pointer—it has no memory. One way to fix this is as follows:
unsigned long *uptr; [...] uptr = malloc(sizeof(unsigned long)); if (!uptr) { [...handle the error...] ...
