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Ian Boyd · Guest

i have having horrible, horrible, horrible, problems using COM from a Delphi
service application. Things that just make no sense and just don't work.
Rather than getting involved in a week long discussion about what the
symptoms i'm experiencing, i'll tell you that i've guessed what the problem
is; and want an answer to this question:

When should i call CoInitialize/Couninitialize from my service application?

Delphi services create a thread to do *something*. My service application
has nothing in it's OnExecute event.
During OnCreate i construct an object that loads COM objects from dlls.
During OnDestroy i nil off those COM object references and destroy my main
object.
During OnPause i call a method of my object that "pauses" it.
During OnResume i call a method of my object that "resumes" it.

Should i call CoInitialize during OnCreate? Isn't OnCreate not yet in a
thread? Is OnCreate called from the context of a thread? If the service
application is a out of process host for COM objects, will those object
methods be called from the service application's main thread or from the
thread Delphi creates?

Should i not be using COM objects during OnCreate if they will be access
later via the delph thread?

Should i be doing:

procedure Service.OnExecute()
var
o: TMyEverythingObject
begin
CoInitializeEx(nil, 0);
try
o := TMyEverythingObject.Create;
try
while not Terminated do
begin
end;
finally
o.Free;
end;
finally
Counitialize;
end;
end;

But then am i allowed to talk to my object during OnPause/OnResume/OnStop?
Are those also executed in the context of the thread? Who calls OnPause? How
is it called? What does it do to the main application thread? What does it
do to the "service" thread? What does it do to OnExecute?

If the service is paused, is the thread paused? Is OnPause just before the
thread is paused?

etc, etc, etc.

What's maddening is that COM is not throwing any exceptions saying i haven't
entered an apartment yet with CoInitialize.

If you're not an up-tight priss, and you want to read what my latest problem
in the long chain of this one "quick change" is, do a google search for:
"Ian Boyd Can a marshalled interface be marshalled?"