Te tas pats, kas ar "null file".
Def.: When referring to computer memory, a null pointer is a command used to direct a software program or operating system to an empty location in the computer memory. Commonly, the null pointer is used to denote the end of a memory search or processing event. In computer programming, a null pointer is a pointer that does not point to any object or function.
http://www.computerhope.com/jargon/n/nullpoin.htm
http://theory.uwinnipeg.ca/gnu/glibc/libc_504.html