Purpose
 
		 
		Indicates if a parameter is included on a call. 
		
 
	  
 
	 
 
	 Parameters
 
		 
		x must be an un-subscripted parameter by address, and the corresponding argument must be declared as OPTIONAL in the ENTRY declaration. 
		
 
	  
 
	 Description
 
		 
		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.