Re: CoCreateInstance() returns E_OUTOFMEMORY
On Feb 1, 11:17 am, "Brian Muth" <bm...@mvps.org> wrote:
"Bala L" <balasubramania...@gmail.com> wrote in messagenews:86d0cf9c-95a9-46fc-aba8-c14ee3b314fc@e4g2000hsg.googlegroups.com...
On Jan 31, 11:33 pm, "Brian Muth" <bm...@mvps.org> wrote:
"Bala L" <balasubramania...@gmail.com> wrote in messagenews:876b2d02-75f1-436f-8457-862411eb5877@v17g2000hsa.googlegroups.com...
I am trying to use a program developed by someone else to interface
with a camera using the SDK. This program runs fine on a particular
laptop, but not on any other machines.
The code tries to initialize the camera object through a function
exposed through a .dll file.
m_pVidControl = new CCameraCtl();
m_pVidControl->Initialize(640,480); // Unhandled exception causes
crash
The program crashes on the second line, and by stepping in to the code
in the .dll, I found the error in the CoCreateInstance() function
call.
int CCameraCtl::Initialize(int width, int height)
{
//init camera capture com
HRESULT hresult;
hresult = CoCreateInstance(CLSID_CDirectShowGrabber, NULL,
CLSCTX_INPROC_SERVER, IID_IFilter, (void **)&(m_pGrabber)); //
Returns out of memory error
// Rest of function
}
The m_pGrabber has a valid address when it enters the Initialize()
function, but is again being reset to NULL after this line.
It doesn't matter what the value is that m_pGrabber holds. CoCreateInstance() is supposed to overwrite that value anyway with a
valid interface pointer if CoCreateInstance() succeeeds.
Did you remember to call CoInitialize()?
Brian
Yes, CoInitialize() is called in the InitInstance(). If it wasn't
being called, then I would expect the program to fail on the other
computer as well. It runs fine on a single laptop, and fails on 2-3
other computers I've tried.
You haven't indicated whether the COM object is built on MFC or ATL. IIRC, the "out of memory" error for early versions of ATL was
misleading, and often occurred when the COM object (or the proxy-stub) wasn't registered properly. Is this an inproc or out-of-proc
COM object?
A good way of testing whether the object is properly registered is to use OLEVIEW and try to instantiate the object. Did you try
that?
Brian
Thanks for all the suggestions. This is the first time I am using COM
objects, and don't have much of an idea about them. I did try to use
the Oleview tool, but was not able to proceed further on that since I
don't know how to use it. However, on comparing the output windows on
the laptop and the desktop during the CoCreateInstance() calls, I
found that some other .dll files were being loaded in the laptop. On
registering these files in the desktop, I am now able to run the
program.
Still have some issues, though. The live display of the camera image
is not showing what the camera actually sees. I am trying to find
other differences between the two implementations to find out what
could be causing this.
Once again, thanks for the help and let me know if you have any
suggestions for what could be causing the displays to be different.
Bala