Creates a unique filename for the current directory.
#include <stdlib.h>
char *mktemp (
char *name);
(IN) Points to a null-terminated string that contains a legal filename with six trailing X's
If successful, returns a pointer to the generated filename; otherwise, returns a NULL pointer if a unique name could not be generated.
The mkstemp function replaces the six X's in the name parameter with a single-byte character. The resulting name is guaranteed to be unique in the current directory. Subsequent calls to this function continue to create unique names for the current directory.