Global Values in DLL not cleared between calls

[Tim Wisseman]

I was caught by surprise. I am not sure if this is working as
designed, but here is what I am seeing.

I am not using multi-threads.

I make a call to a DLL, the DLL call uses globals.
(Its own globals)

When I make a second call to the DLL the globals still have the
values that were put their from the first call. Nothing was
cleared.

Is this normal and by design? For some reason I was thinking
that the globals in a DLL are all reset at the beginning
of each call, so I was surpised.

Tim




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[Paul Squires]

Tim,

Are you using this DLL in a Visual basic app - specifically are
you starting and restarting from inside the VB design environment???

I had a similar problem with my Cheetah DLL where the DLL does
not unload between "restarts" and the values remained. I had to
create a special function that essentially killed the DLL in
memory by calling the Windows API function FreeLibrary.



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Paul Squires
www.PlanetSquires.com
mailto:[email protected]
[email protected]
</A>

[Tim Wisseman]

My program is all PBDLL.
A Power Basic EXE is calling a Power Basic DLL.

Tim


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[Kev Peel]

Tim,

If I understand you correctly, you are making two or more calls to the same DLL within your application. The global (and static) variables in the DLL will retain their values for the duration of the calling program, ie:

1./ Call Foo1 in the dll, and set global 'g' (in the dll) to 1 from foo1
2./ Call Foo2 in the dll, Foo2 displays a msgbox showing content of 'g', it will be 1.

This is 'by design'

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Kev G Peel
KGP Software, Bridgwater, UK.
mailto:[email protected][email protected]</A>

[Michael Mattias]

Expected behavior: GLOBALs in DLLs maintain their value until changed or the DLL is unloaded.

MCM

[Tim Wisseman]

I had no idea it worked like that.

Thanks guys!

Tim


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[Lance Edmonds]

Think of it this way: a GLOBAL works like a STATIC variable that is shared with _all_ subs/functions in a module.

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Lance
PowerBASIC Support
mailto:[email protected][email protected]</A>