CHECKSTG

CHECKSTG returns a bit(1) value which indicates whether a specified pointer value is the start of a piece of uncorrupted allocated storage. If no pointer value is supplied, CHECKSTG determines whether all allocated storage is uncorrupted. To use this built-in function, you must also specify the CHECK(STORAGE) compile-time option.

p

Pointer expression.

When an allocation is made, it is followed by eight extra bytes which are set to 'ff'x. The allocation is considered uncorrupted if those bytes have not been altered.

The pointer expression must point to storage allocated for a BASED variable.