Re: [Mingw-users] OLE program crash

[Luke D. <cod...@ho...>]

Are you using gcc 2.95.3 or gcc 3.1? Are you using C or C++? If you are
using the old compiler, are you building all objects with -fvtable-thunks?
Have you tested this code at all with a different compiler, such as MSVC?

Sorry, but I have to ask the obvious questions first.

Luke

----- Original Message -----
From: "Dirk McCormick" <mcc...@cs...>
To: <min...@li...>
Sent: Friday, July 05, 2002 1:32 PM
Subject: [Mingw-users] OLE program crash


> Hi.
> I'm having a rather perplexing problem trying to implement a Drop Source
> for a ListView.
> Every time I drag something, it causes a "This program has performed an
> illegal operation ..." error and crashes.
> I've implemented interfaces for IDropSource, IDataObject (required by
> IDropSource) and IEnumFORMATETC (required by IDataObject)
>
> GDB tells me that the sequence of events leading up to the crash are:
> DoDragDrop() is called, with the IDropSource object and an IDataObject
> object as parameters.
> In DoDragDrop(), some of the IUnknown methods of IDataObject are called.
> Specifically, QueryInterface is called 3 times, and on the third
> occasion with IID_Unknown as a parameter, from which S_OK is returned.
> QueryInterface is then called 2 more times, both unsuccessfully (S_OK is
> not returned, ie the REFIID parameter wasn't IID_IDropSource or
> IID_IUnknown)
> Immediately following the return from the second QueryInterface call,
> the program crashes:
>
> Program received signal SIGSEGV, Segmentation fault.
> 0x7ff5590b in _libuser32_a_iname ()
> (gdb) s
> Single stepping until exit from function _libuser32_a_iname,
> which has no line number information.
>
> Program exited with code 037777777777.
>
>
> Any help would be greatly appreciated!
> If more information is needed, such as GDB output or source code, please
> ask.
> (I plan to release the source once I've got a decent interface working)
> I'm really just looking for any hint of what might be going wrong.
>
> This is the whole error given by windows when the program crashes:
>
> MYFTP caused an invalid page fault in
> module OLE32.DLL at 0167:7ff5590b.
> Registers:
> EAX=00000074 CS=0167 EIP=7ff5590b EFLGS=00010213
> EBX=004f51c0 SS=016f ESP=0081f1a4 EBP=00000000
> ECX=004f51c4 DS=016f ESI=004110d4 FS=2a0f
> EDX=00000000 ES=016f EDI=004f5208 GS=0000
> Bytes at CS:EIP:
> 89 38 8b c3 5d 5f 5e 5b 83 c4 14 c2 10 00 8d 73
> Stack dump:
> 009405c0 7ff2e2b0 004f522c 009405c0 7ff2e2a0 0081f1cc 009405c0 0081f258
> 00000000 00000000 009405c0 004f0000 00000000 00000074 7ff21520 7ffce00c
>
>
> Thanks in advance.
> Dirk