MFC, Multithreading in Visual C++ programmes

Multithreading in Visual C++ programmes

Author	Message
Charlie Ferrer #1 / 4	Multithreading in Visual C++ programmes Hi there, I have some C++ code that calls a fortran routine which takes between 60seconds and four or five minutes to complete and return back. The actual FORTRAN code is working fine (in the de{filter} I can watch variables and check that they're being changed correctly). However, once control returns back from the routine the programme crashes in thrdcore.cpp at the line: if (IsIdleMessage(&m_msgCur)) { bIdle = TRUE; lIdleCount = 0; } 15bytes in, actually, at the code line 5F438D3D call dword ptr [edx+6Ch] (if that helps, which I doubt). My guess is that the FORTRAN routine is taking so long that it is blocking programme message processing. Is this likely/possible? Because I'm fairly new to all this, my next guess may well sound stupid, but I think I should start the FORTRAN routine as a separate thread. Reading up on this, it appears that routines started in separate threads can only have one argument passed to them. If so, then I don't know what to do as the FORTRAN routine requires six parameters. Any suggestions welcome, Charlie
Sun, 29 Sep 2002 03:00:00 GMT

Dave Smit #2 / 4	Multithreading in Visual C++ programmes Charlie, I don't know the answer to your crash, but I can answer you thread parameter question. The single parameter passed into the thread procedure can be a pointer to a structure containing the several parameters needed by your Fortran function. -- Dave Smith MCSE, MCT, MVP Quote: >Hi there, >I have some C++ code that calls a FORTRAN routine which takes between >60seconds and four or five minutes to complete and return back. >The actual FORTRAN code is working fine (in the de{filter} I can watch >variables and check that they're being changed correctly). >However, once control returns back from the routine the programme crashes in >thrdcore.cpp at the line: > if (IsIdleMessage(&m_msgCur)) > { > bIdle = TRUE; > lIdleCount = 0; > } >15bytes in, actually, at the code line >5F438D3D call dword ptr [edx+6Ch] >(if that helps, which I doubt). >My guess is that the FORTRAN routine is taking so long that it is blocking >programme message processing. Is this likely/possible? >Because I'm fairly new to all this, my next guess may well sound stupid, but >I think I should start the FORTRAN routine as a separate thread. >Reading up on this, it appears that routines started in separate threads can >only have one argument passed to them. If so, then I don't know what to do >as the FORTRAN routine requires six parameters. >Any suggestions welcome, >Charlie
Sun, 29 Sep 2002 03:00:00 GMT

Niki Estne #3 / 4	Multithreading in Visual C++ programmes I have a C++ program that calls a C++ routine that takes about 15 minutes to execute (if there is enough virtual memory, that is). I've never had the problem you have, and I've never heard about "a function taking too long" from windows (of course, I've heard that often enough from my customers...). Is it possible that your code does some message processing (like PumpMessage, PeekMessage, ...)? This could disturb MFC. Niki Quote: > Hi there, > I have some C++ code that calls a FORTRAN routine which takes between > 60seconds and four or five minutes to complete and return back. > The actual FORTRAN code is working fine (in the de{filter} I can watch > variables and check that they're being changed correctly). > However, once control returns back from the routine the programme crashes in > thrdcore.cpp at the line: > if (IsIdleMessage(&m_msgCur)) > { > bIdle = TRUE; > lIdleCount = 0; > } > 15bytes in, actually, at the code line > 5F438D3D call dword ptr [edx+6Ch] > (if that helps, which I doubt). > My guess is that the FORTRAN routine is taking so long that it is blocking > programme message processing. Is this likely/possible? > Because I'm fairly new to all this, my next guess may well sound stupid, but > I think I should start the FORTRAN routine as a separate thread. > Reading up on this, it appears that routines started in separate threads can > only have one argument passed to them. If so, then I don't know what to do > as the FORTRAN routine requires six parameters. > Any suggestions welcome, > Charlie
Sun, 29 Sep 2002 03:00:00 GMT

Scott McPhillip #4 / 4	Multithreading in Visual C++ programmes Quote: > Hi there, > I have some C++ code that calls a FORTRAN routine which takes between > 60seconds and four or five minutes to complete and return back. > The actual FORTRAN code is working fine (in the de{filter} I can watch > variables and check that they're being changed correctly). > However, once control returns back from the routine the programme crashes in > thrdcore.cpp at the line: > if (IsIdleMessage(&m_msgCur)) > { > bIdle = TRUE; > lIdleCount = 0; > } > 15bytes in, actually, at the code line > 5F438D3D call dword ptr [edx+6Ch] > (if that helps, which I doubt). > My guess is that the FORTRAN routine is taking so long that it is blocking > programme message processing. Is this likely/possible? > Because I'm fairly new to all this, my next guess may well sound stupid, but > I think I should start the FORTRAN routine as a separate thread. > Reading up on this, it appears that routines started in separate threads can > only have one argument passed to them. If so, then I don't know what to do > as the FORTRAN routine requires six parameters. > Any suggestions welcome, > Charlie When you call one language from another a likely suspect is a calling convention mismatch. Single-step through the assembly language and note the stack value (ESP in the register window) before the call and after the FORTRAN function returns. If it doesn't match a crash will soon follow. A penny says your edx value came out of the wrong place in the stack after the return. To use a thread put all the parameters in a struct and pass a pointer to the struct to a C thread function. Then you can take the struct apart and pass it however you need to into the FORTRAN function. -- Scott McPhillips [VC++ MVP]
Sun, 29 Sep 2002 03:00:00 GMT

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