Dave,

Create the following class:

*-- Class: cusgfp (c:\program files\microsoft visual studio\vfp98\testgfp.vcx)
*-- ParentClass: custom
*-- BaseClass: custom
*-- Time Stamp: 08/27/99 08:47:11 AM

DEFINE CLASS cusgfp AS custom

	cSetClassLib = ""
	Name = "cusgfp"

	PROCEDURE Init
		This.cSetClassLib = SET("CLASSLIB")
		SET CLASSLIB TO
	ENDPROC

	PROCEDURE Destroy
		LOCAL lcSetClassLib

		lcSetClassLib = This.cSetClassLib
		SET CLASSLIB TO &lcSetClassLib
	ENDPROC

ENDDEFINE

Now from the Command Window, type:

oCrash = NEWOBJECT("cusgfp", "c:\program files\microsoft visual studio\vfp98")
RELEASE oCrash
oCrash = NEWOBJECT("cusgfp", "c:\program files\microsoft visual studio\vfp98")

BLAMO

The Invalid Page Fault occurs when you instantiate the object the second time. This makes sense due to my understanding of an implicit SET CLASSLIB when using NEWOBJECT for object instantiation.

While one may say that someone would be insane to use a class like the one above, some objects instantiate other objects which instantiate other... and so on. I found this problem with my framework's application object which fires an environment object used to set/reset global SETS - including SET CLASSLIB.



>Please provide a code sample. Your steps below are confusing to me.
>
>Thanks,
>
>Dave
>
>>I have found a special case that is guaranteed to cause a VFP Invalid Page Fault and, therefore, should be avoided:
>>
>>- NEWOBJECT(CLassName, CLassLibrary) is used to instantiate an object and ;
>>
>>- SET CLASSLIB TO is issued before the instantiation of the object is complete and ;
>>
>>- SET CLASSLIB TO ClassLibrary (same class library) is issued after the instantiation of the object is complete and ;
>>
>>- The object is released and ;
>>
>>- NEWOBJECT(CLassName, CLassLibrary) is used to instantiate the object again, THEN ;
>>
>>blamo - VFP Invalid Page Fault every time.