How to load a DLL as a local server

Question

hi guys, I really need help...

I have implemented a COM component (i.e A.dll) with IDL, also coded a wrapper DLL (B.dll) for that component. I have implemented required export functions for DLL "A" and registered it with "regsvr32.exe".

Problem is that I have 3 EXE files that uses B.dll to access methods of A.dll. But, I could not manage to create a local server for A.dll, therefore every EXE loads a new A.dll and B.dll. I want to load A.dll only once, and need to realize this functionality in B.dll. Last statement is open for discussion also.

However, I could not manage to find any useful example or resource regarding this problem. Any help will be appreciated, thanks in advance.

Answer 1

There's no such thing as "create a local server". In-proc server has to be loaded into each consumer process, there's no way around that - each consumer is a separate process, so it has its own copy of code and data.

In order to have a single process executing COM server code for all of the consumers you have to create an out-proc server. To do the latter you can either reengineer your COM server or try to use COM+ server application. This way you can have a separate process running the COM server code several consumers can connect to.

Answer 2

A DLL mediated by COM is known as an in-process server. Which suggests your problem: it will always be mapped into the memory space of its clients, just like any other DLL. Similarly any DLLs it loads will be mapped into the original process. It is not clear from your question why you don't want to use a DLL. If it is to save resources then consider that only data will be duplicated; the code will only be loaded once. If it is because you want them to share data, then consider using shared memory. If you really want all three .exe's to be served by an instance then what you need is a COM local server, which will be implemented by an .exe, not a .dll.