Null pointer - Definition and Overview

In the C Programming Language, a Null pointer is a distinct pointer value which is "guaranteed to compare unequal to a pointer to any object or function." A null pointer is different than a uninitialized pointer. A null pointer is known not to point to any particular object or function but an uninitialized pointer might point anywhere. There is a null pointer for each pointer type, and the internal values may differ. These values are not important to the programmer, but rather the compiler.