is there anyone familiar with COM? I met problem when changed project from MFC to Qt

hskoglund

Hi, what error do you get from your CoInitializeEx() call? Try something like:

HRESULT hr = CoInitializeEx(NULL, COINIT_MULTITHREADED);
qDebug() << hr;

opengpu

@hskoglund that DLL with COM is not Qt program...

mrjj

@opengpu
Hi
then use std::cout to show the HRESULT.
It can give hints about why its not loading,.

What im a bit puzzled about if that is the same DLL used in the MFC app, and you did not change
the actual DLL code. why should it then stop working?

opengpu

the DLL is the same...
and i wiil log out the errorcode

opengpu

anyone familiar ?

mrjj

@opengpu
did you get HRESULT hr out ?

opengpu

@mrjj HRESULT = -2147417850

mrjj

@opengpu
ok. super. Hopefully mr hskoglund can get something out of that.

aha_1980

https://en.m.wikipedia.org/wiki/HRESULT describes tools to decode HRESULTs

Christian Ehrlicher

@opengpu said in anyone familiar with COM? i met problem when changed project from MFC to Qt:

-2147417850

= 0x80010106

https://stackoverflow.com/questions/11708497/com-library-initialization-failed-with-code-0x80010106-in-c-sharp

"This is a bug in the DLL you are using. A DLL should never call CoInitializeEx() on a thread that it didn't create. "

hskoglund

Hi, what happens to your .DLL if you skip (comment out) the call to CoInitializeEx()?

opengpu

0x80010106

opengpu

This post is deleted!

opengpu

#include "stdafx.h"

BOOL APIENTRY DllMain( HMODULE hModule,
                       DWORD  ul_reason_for_call,
                       LPVOID lpReserved
					 )
{
	switch (ul_reason_for_call)
	{
	case DLL_PROCESS_ATTACH:
	case DLL_THREAD_ATTACH:
	case DLL_THREAD_DETACH:
	case DLL_PROCESS_DETACH:
		break;
	}
	return TRUE;
}

opengpu

APIImp::APIImp()
{
	//if(!SUCCEEDED(CoInitialize(NULL)))
	HRESULT ret = CoInitializeEx(NULL, COINIT_MULTITHREADED);
	if(!SUCCEEDED(ret))
	{
		//return;
	}

	initialize();
}

opengpu

@hskoglund why you asked this question?
i didnot return when failed to CoInitializeEx(NULL, COINIT_MULTITHREADED);
it seems worked...

opengpu

APIImp::APIImp()
{
	//if(!SUCCEEDED(CoInitialize(NULL)))
	HRESULT ret = CoInitializeEx(NULL, COINIT_APARTMENTTHREADED);
	if(!SUCCEEDED(ret))
	{
		return;
	}

	initialize();
}

i use COINIT_APARTMENTTHREADED instead of COINIT_MULTITHREADED, and this works fine for me.