Function pointer changing or overwritten?

[NickPaul]

    void Receiver::start(){
        running = true;
        std::cout << "updateThread " << (void*)updateThread << std::endl;
        _beginthreadex(NULL, 0, &updateThread, this, 0, pThreadHandle);
    }

Output:

updateThread 0x402b67

Call stack for segmentation fault:

#0 7C8107C6	KERNEL32!CreateRemoteThread() (C:\WINDOWS\system32\kernel32.dll:??)
#1 00402B67	gps::DataManager::getMeasDataAtTime(this=0xffffffff, gpsTime=0, threshold=2.8900590577460985e-305, retData=@0x0) (C:\Documents and Settings\PC_XPlane\Desktop\WTF\Receiver.cpp:68)
#2 7C81084D	KERNEL32!CreateThread() (C:\WINDOWS\system32\kernel32.dll:??)
#3 77C3A443	msvcrt!_beginthreadex() (C:\WINDOWS\system32\msvcrt.dll:??)
#4 00402C23	gps::Receiver::start(this=0xb44d90) (C:\Documents and Settings\PC_XPlane\Desktop\WTF\Receiver.cpp:109)
#5 004099CD	gps::AttitudeSolver::init() (C:\Documents and Settings\PC_XPlane\Desktop\WTF\AttitudeSolver.cpp:125)
#6 0040F01B	gps::AttitudeSolver::run() (C:\Documents and Settings\PC_XPlane\Desktop\WTF\AttitudeSolver.cpp:147)
#7 0040F059	main() (C:\Documents and Settings\PC_XPlane\Desktop\WTF\AttitudeSolver.cpp:783)

See the address of gps::DataManager::getMeasDataAtTime? It is the "same" as updateThread...

What is going on?

Nick.

[kbw]

We have no idea what type pThreadHandle is or what value you've assign to it or what updateThread does ...

[NickPaul]

Sorry:

uintptr_t _beginthreadex( 
   void *security,
   unsigned stack_size,
   unsigned ( *start_address )( void * ),
   void *arglist,
   unsigned initflag,
   unsigned *thrdaddr 
);

And updateThread does nothing (cout << "In here" << std::endl;). See I'm sure updateThread is meant to be called after "KERNEL32!CreateThread()" but as you can see getMeasDataAtTime() is called - which is completely random... hence why I pointed out the addresses. updateThread is a function defined in namespace gps, it is not a member function.

Anyway, I'll try recreate the problem in a small program.

Nick.

[kbw]

What compiler warning level are you compiling at? I'd expect a warning about passing the address of a function and about not casting this in:

    _beginthreadex(NULL, 0, &updateThread, this, 0, pThreadHandle);

Anyway, as the debugger says, CreateThread is definitely calling gps::DataManager::getMeasDataAtTime.

I know the signature of system calls as those are well documented. I was hoping you'd post your code as that's likely where the error lies.