Creates a new file with a unique name in the current directory.
#include <stdlib.h>
int mkstemp (
char *name);
(IN) Points to a null-terminated string that contains a legal filename with six trailing X's.
If successful, returns a file descriptor; otherwise, returns -1 if a unique name could not be generated.
The mkstemp function replaces the six X's in the name parameter with an alpha-numeric sequence. The resulting filename is guaranteed to be unique in the current directory. Subsequent calls to this function continue to create unique names for the current directory.