Indicates if a parameter is included on a call.
PRESENT(x)
x must be an un-subscripted parameter by address, and the corresponding argument must be declared as OPTIONAL in the ENTRY declaration.
The PRESENT built-in function returns "true" i.e. a BIT(1) value equal to '1'B if the specified parameter is supplied when calling the containing procedure.
The PRESENT built-in accepts Level-1 structure or union arguments.
None.