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After I posted this article and a shorter one titled Class exporter now a pre-build task (DCL) I decided I needed to deal with a circular reference problem in the class exporter, which now uses DCL_System_IO_AsciiFile to read its list of class headers to parse from a text file.

Originally CreateDCLExportFile made use of DevRoadmapsClarion.DLL, but because CreateDCLExportFile is now a pre-build task for the class library there's a risk that a change to the class library could cause a runtime failure which would break the class library build. With the build broken, how do I then create the EXP so the build can succeed? Big problem.

But wait, that's no problem at all. I can do the same thing with CreateDCLExportFile that I did with ClarionTest - compile in the required classes so I don't need the DLL. Brilliant!

Except when I did that, CreateDCLExportFile GPFd.

I actually resorted to the debugger to see what was the problem. And I found that in an EXE my AsciiFilePool class was not being instantiated. Why, I can't imagine.

The fix was to change AsciiFilePool to a typed class and set up a reference:

AsciiFilePoolType                       class(DCL_System_Pool),type
Construct                                   procedure
										end
AsciiFilePoolInstance                   &AsciiFilePoolType

The first line of my DCL_System_IO_AsciiFile.Construct method now has this line:

if AsciiFilePoolInstance &= null then AsciiFilePoolInstance &= new AsciiFilePoolType.

This way I'm guaranteed to have a pool instance.

I find it quite strange that a module-level instance should need to be instantiated for EXEs but not DLLs, but there it is. If anyone can shed light on this please do so.