NULLIFY statement
Standard: F77 F90 F95 F2003
  Example Program
NULLIFY ( variable [ , variable ]... )

Each variable must be a pointer.

Sets the status of each pointer variable to “disassociated”, breaking any connection between the pointer and any previous target.

A pointer can also become disassociated by pointer assignment from a disassociated pointer. The NULL intrinsic function returns disassociated pointers of any type.

The ASSOCIATED intrinsic function returns false for a disassociated pointer. A disassociated pointer must not be referenced or defined.

ASSOCIATED intrinsic function, NULL intrinsic function, POINTER attribute, TARGET attribute.