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Hi,
columbos14927 wrote: 1.The painting on the window is done by some function that is provided by frame grabber manufactorer.
Have you considered contacting the manufacturer?
columbos14927 wrote: 2.When i resize the window the App freezes and not responding to anything there are no error codes.
If you want to be a good software engineer then you will need to learn how to use your debugger.
When your application freezes:
1.) Execute a Debug build of your application from Visual Studio with debugger attached.
2.) Inside your Visual Studio you need to do a 'Break All'
3.) In Visual Studio make sure that Debug->Windows->Thread is visible. If you are a keyboard kind of guy this would be: CTRL+ALT+H
4.) In Visual Studio make sure that Debug->Windows->Callstack is visible. If you are a keyboard kind of guy this would be: CTRL+7
5.) Each thread is listed in the window along with the top of the callstack.
6.) You can select a thread in the Visual Studio debugger... and the 'CallStack' window will show the callstack associated with that thread.
Now you will be able to find what is causing the freeze.
Sometimes I find that WinDbg[^] is more powerful. If you want to use this then you would:
1.) Compile a Debug version of your application with Visual Studio.
2.) Download and install Debugging Tools for Windows[^]
3.) Launch your application from WinDbg or conversely... attach to the running instance.
4.) Wait for the freeze, or invoke it.
5.) When it freezes... Choose Debug->Break from the menu or from keyboard CTRL+BREAK
6.) Issue the command: !analyze -v -hang to have WinDbg analyze any hangs.
7.) Inspect the callstack of all threads and look for possible causes to the hang: ~*kv 250
8.) Another useful command is: !runaway[^] for having a look at thread times. Sometimes a hanging thread is spinning in an infinite loop and you can see which thread is hung... by observing that its consuming all of the thread times.
9.) If you still have not found it yet... it could be the main thread in a wait state... infinitely waiting to obtain a critical section or mutex... you can issue an !ntsdexts.locks[^] to look for critical sections and waiting threads.
If you are using WinDbg to debug a 32 bit executable under WOW64 then you might need to issue: .load wow64exts; .effmach x86
Someone should probably write and article or Tip/Trick about this.
Best Wishes,
-David Delaune
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Client area painting must occur in the main Windows thread. The problem is that the thread grabbing the frames is not the main Windows thread. So while it's drawing to the client area, any old windows message might come along and cause a crash as the two threads bump into each other. This is especially true when resizing - there are lots of "PAINT" messages hitting the dialog, and there's a good chance that PAINT handling is happening at the same time your other thread is drawing to the client area. Result is a crash.
The solution is to have the main windows thread do the drawing. So you'll need a way to move the frames from the grabber thread to the windows thread, and signal your dialog that it's time to draw a new frame.
You could try using a custom message, e.g. WM_USER+<n> ( see here: http://www.ucancode.net/Visual_C_MFC_Example/RegisterWindowMessage-WM_USER--VC-Example.htm[^] ). You can allocate a buffer to hold the frame and pass the pointer to that buffer as the LPARAM. The frame-grabber thread then just needs to PostMessage(...) to the Dialog.
On the Dialog side, add the handler for the WM_USER+<n> message to draw the image pointed to by LPARAM. Don't forget to deallocate that buffer when done!
This is just one example for moving information from some "outside" thread to the main windows thread. You can probably find many others.
- Bob
Bob Ciora
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Another way to handle this may be to pause your camera app during dialog paint and resize functions.
Assuming the API allows this.
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Is there a function for determining the size of a DLL image as it is loaded into the process address space?
How do we determine the base address of a loaded DLL?
Also, is there some way to tell the system to load a DLL at a base address that I specify, regardless of the image's preferred base address?
The difficult we do right away...
...the impossible takes slightly longer.
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There's some good info on related topic in here: Hooks and DLLs[^]
"Real men drive manual transmission" - Rajesh.
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Thanks. I'll check that out.
The difficult we do right away...
...the impossible takes slightly longer.
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Hi Richard,
Richard Andrew x64 wrote: How do we determine the base address of a loaded DLL?
The HMODULE that you get from the GetModuleHandle function[^] is the same as the base address. If you are writing MFC applications... this will be the same address returned from AfxGetResourceHandle [^]. The AfxGetInstanceHandle[^] function is actually returning the base address of the main application image.
If you are using a Microsoft compiler then you also have access to an extern variable __ImageBase which can be used to access the these base addresses. Because it is equal to an HMODULE you can also use this variable for loading resources[^].
Now that we have the base address we can read the PE image headers [^]and check for a size:
DWORD GetSizeOfImage(HMODULE hModule)
{
DWORD dwSize = 0;
PIMAGE_DOS_HEADER pDOSHeader = (PIMAGE_DOS_HEADER)hModule;
PIMAGE_NT_HEADERS pNTHeader = (PIMAGE_NT_HEADERS)((PBYTE)hModule + pDOSHeader->e_lfanew);
if(IMAGE_NT_SIGNATURE == pNTHeader->Signature)
{
PIMAGE_FILE_HEADER pFileHeader = (PIMAGE_FILE_HEADER)((PBYTE)&pNTHeader->FileHeader);
PIMAGE_OPTIONAL_HEADER pOptionalHeader = (PIMAGE_OPTIONAL_HEADER)((PBYTE)&pNTHeader->OptionalHeader);
if(IMAGE_NT_OPTIONAL_HDR32_MAGIC == pNTHeader->OptionalHeader.Magic)
{
dwSize = pNTHeader->OptionalHeader.SizeOfImage;
}
}
return dwSize;
}
Richard Andrew x64 wrote: Also, is there some way to tell the system to load a DLL at a base address that I specify, regardless of the image's preferred base address?
Maybe... check out the /FIXED (Fixed Base Address)[^] linker option.
I consider fixed base addresses to be an insecure option... I highly recommend that all software engineers support a dynamic base address.
PE images with support for ASLR[^] will have the IMAGE_DLL_CHARACTERISTICS_DYNAMIC_BASE bit set in the PE image characteristics. These modules are essentially saying 'put me anywhere you want... I don't care' and the kernel pseudo-randomly chooses an address to map the image.
PE images without support for ASLR... the NT kernel will make an attempt to load the image at its preferred address at pNTHeader->OptionalHeader.ImageBase. If the address is already allocated the kernel will make an attempt to map the image at another address and apply its fixups.
Best Wishes,
-David Delaune
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Thanks for a terrific reply. I certainly appreciate the info!
The difficult we do right away...
...the impossible takes slightly longer.
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Hey,
Your very welcome. I just happened to be researching ASLR very recently while developing a device driver for extending the NEMET security application[^].
In case I did not answer your second question very clearly... no you cannot make the NT loader map a module to an arbitrary address other than the preferred address... it will choose the address itself. You *could* however manually map the module yourself using a technique similar to what was described ages ago... by Joachim Bauch.
Best Wishes,
-David Delaune
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Hello guys,
I met a trouble when i try to modify a hardware's property via API.
It's a USB2COM which is able to perform high-baudrate serial communication. Cause i hope it could update data within 1ms, i have to modify the its update property(latency-timer) from 16ms(default) to 1ms.
Of course i could do that with
[My computer -> System property -> Hardware -> Device Manager ... ], just like the steps described in the following setting manual.
Here is a setting manual, USB2COM Setting Manual. There is the detail description about latency-timer setting, @ Page16 3.3.2.1 .
But i want to know if there is may be another more elegant method via API in shell32.dll or user32.dll?
Control_RunDLL in shell32.dll brings me little help, cause it could do nothing more than shell("Control.exe sysdm.cpl ,2"). What i want is a methed can just modify the number from 16 to 1...
USB2COM's drivers couldnt help me, either, cause no documentation or interface is given.
Could someone give me some advice? I'll be very appreciated.
Thanks.
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Unless you are comfortable working with EIA / RS232 / COM hardware , this can get scarry.
What you need is to get to <b>DCB - data communication block</b> and than you can manipulate most, and I stress most, of the COM paramaters. There are articles about COM in here, but they usually do not explain what is happening in hardware when it comes to working with COM.
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Thanks a lot. Vaclav_Sal
My problem has been solved.
I found the setting interface(in ftd2xx.dll) from FTDI knowledge base.
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I am looking for a way to have a dynamic ( run time) array of afx_msg functions.
I have tried this with some success.
CPtrArray pArray;
pArray.Add((void*) OnFunctionkeysCallsate());
pArray.Add((void*) OnWindowNewlogview());
int iTest = pArray.GetSize();
iTest = pArray.GetUpperBound();
void * pElement = pArray.GetAt(0);
void * pElement_1 = pArray.GetAt(1);
Here are my problems
1. The GetSize returns 2 but GetAt(0) and GetAt (1) return same pointer. Why?
2. The Add method adds the function to the pointer array just fine but also runs it. I can live with that but like to know why it does that.
3. I have no clue what GetAt actually returns and how to use it.
4. I realize this approach still does not provide for dynamic add of a function. Working on that – I guess passing function as variable documentation should help.
5. Is it really “legal” to change the afx_msg function from void to void * as I did?
Thanks for your help. It is really appreciated.
Have a great 2012.
Vaclav
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pArray.Add((void*) OnFunctionkeysCallsate());
Calls the OnFunctionkeysCallsate() function and stores the result of that call into pArray. If I understand you correctly, this is not what you want. Instead, you want the address of the function, not the result of invoking the function. Remove the "()".
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Thanks, pretty stupid mistake on my part as far as caling the function.
Now I need to really figure out how to pass the function as void pointer. Or maybe I need to change the CPtrArray?
I'll work on that.
-- modified 2-Jan-12 22:54pm.
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Chuck O'Toole wrote: pArray.Add((void*) OnFunctionkeysCallsate());
partially agree, however i believe you missed & before function name at time of addition to ptrarray collection
"Opinions are neither right nor wrong. I cannot change your opinion. I can, however, change what influences your opinion." - David Crow
Never mind - my own stupidity is the source of every "problem" - Mixture
cheers,
Alok Gupta
VC Forum Q&A :- I/ IV
Support CRY- Child Relief and You
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Sorry, I don't see any '&' in the original post and it does not appear to be edited. Which '&' are you talking about?
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Chuck O'Toole wrote: Sorry, I don't see any '&' in the original post and it does not appear to be edited. Which '&' are you talking about?
Actually I meant to say, you need to store the address of function to the CPtrArray, if you try to compile as you mentioned in your post, you will see compiler error as mentioned by actual poster in same thread!
"Opinions are neither right nor wrong. I cannot change your opinion. I can, however, change what influences your opinion." - David Crow
Never mind - my own stupidity is the source of every "problem" - Mixture
cheers,
Alok Gupta
VC Forum Q&A :- I/ IV
Support CRY- Child Relief and You
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OK gurus, I need some serious help here. I am over my head with this one, really.
How do I pass afx_msg function to the CPtrArray?
I understand that CPtrArray wants void* pointer, but the compiler still complains and I really do not understand the error codes.
Here is the code and the compiler errors. The first afx_msg function still retruns void*, just FYI, if it makes any difference now.
Thanks for your help.
pArray.Add((void*) (OnFunctionkeysCallsate));
pArray.Add((void) (OnWindowNewlogview));
MainFrm.cpp
E:\0 OpenLog\V1\TCC\MainFrm.cpp(683) : error C2440: 'type cast' : cannot convert from 'void *(__thiscall CMainFrame::*)(void)' to 'void *'
There is no context in which this conversion is possible
E:\0 OpenLog\V1\TCC\MainFrm.cpp(684) : error C2664: 'Add' : cannot convert parameter 1 from 'void' to 'void *'
Expressions of type void cannot be converted to other types
Error executing cl.exe.
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if your customer allow you to use stl and function OnFunctionkeysCallsate and OnWindowNewlogview have same signature, you can use this piece of code to achieve same:-
void Function1(int i)
{
cout<<"Hello in Function 1 Number " <<i;
}
void function2(int i)
{
cout<<"Hello in Function 2 Number " <<i;
}
typedef void (*MySingleArgFunction) (int);
vector<MySingleArgFunction> vecFuncPtr;
vector<MySingleArgFunction>::iterator it;
vecFuncPtr.push_back(&Function1);
vecFuncPtr.push_back(&function2);
it=vecFuncPtr.begin();
while(it!=vecFuncPtr.end())
{
(*it)(20);
it++;
}
and if still insist on CPtrArray, so here is the pointer to solve above problem :-
you missed a & in
Vaclav_Sal wrote: pArray.Add((void*) (OnFunctionkeysCallsate));
pArray.Add((void) (OnWindowNewlogview));
which should be written as
pArray.Add((void*) &OnFunctionkeysCallsate);
"Opinions are neither right nor wrong. I cannot change your opinion. I can, however, change what influences your opinion." - David Crow
Never mind - my own stupidity is the source of every "problem" - Mixture
cheers,
Alok Gupta
VC Forum Q&A :- I/ IV
Support CRY- Child Relief and You
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Thanks for your reply.
I have already tried adding &. The compiler does not like it.
pArray.Add((void*)&OnFunctionkeysCallsate);
And here is the error message
E:\0 OpenLog\V1\TCC\MainFrm.cpp(683) : error C2276: '&' : illegal operation on bound member function expression
I'll take a look at the vector method.
I am also looking at MFC CMenu.
Vaclav
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Vaclav_Sal wrote: have already tried adding &. The compiler does not like it.
pArray.Add((void*)&OnFunctionkeysCallsate);
And here is the error message
ahh i understand, i believe OnFunctionkeysCallsate is the function defined in the class, if yes then you have to put the code like this:-
pArray.Add((void*)&YouClassNameWhereFunctionISDefines::OnFunctionkeysCallsate);
"Opinions are neither right nor wrong. I cannot change your opinion. I can, however, change what influences your opinion." - David Crow
Never mind - my own stupidity is the source of every "problem" - Mixture
cheers,
Alok Gupta
VC Forum Q&A :- I/ IV
Support CRY- Child Relief and You
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Sorry, still no go
Here is the compiler error message:
MainFrm.cpp
E:\0 OpenLog\V1\TCC\MainFrm.cpp(685) : error C2589: '&' : illegal token on right side of '::'
E:\0 OpenLog\V1\TCC\MainFrm.cpp(685) : error C2059: syntax error : '::'
It seems that this should work. BTW it is all in MainFrm.cpp
pArray.Add((void*)CMainFrame::&OnFunctionkeysCallsate);
Unless you are just curious why it does not, you can just drop it. I am still looking at the CMenu , maybe that will work.
I basically need an array of function pointers I can execute in desired sequence.
Thanks for all your help.
Vaclav
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I'm working on a class array, but I thought it would structure my data different.
I'm working with this code below. I was hoping it would create a single object, with 2 internal members of [0] and [1] creating a single object uaListBoxPtrArray with 2 members [0] Tim and [1] John, Tim and John being inside uaListBoxPtrArray.
But it looks like it creates separate objects
uaListBoxPtrArray[0] which is Tim
uaListBoxPtrArray[1] which is John
and I would have to pass uaListBoxPtrArray[0], uaListBoxPtrArray[1] to a function.
I want to be able to pass the single object to a function in the future, and not separate objects. pass uaListBoxPtrArray by itself, with Time and John inside it.
Q: Is my result or implementation correct?, and that this is the correct result format for the method below?. Or do I now need to work on the constructor, to form a single object of records.
DWORD dwCount;
DB_UserAccount dbUA;
dwCount = dbUA._get_UserAccount_Listbox_Count();
UA_Listbox **uaListBoxPtrArray;
uaListBoxPtrArray = new UA_Listbox*[dwCount];
uaListBoxPtrArray[0] = new UA_Listbox;
uaListBoxPtrArray[0]->iUserID = 47;
uaListBoxPtrArray[0]->szFirstName = L"Tim";
uaListBoxPtrArray[0]->szLastName = L"Parker";
uaListBoxPtrArray[0]->szAccountName = L"tparker";
uaListBoxPtrArray[1] = new UA_Listbox;
uaListBoxPtrArray[1]->iUserID = 48;
uaListBoxPtrArray[1]->szFirstName = L"Joe";
uaListBoxPtrArray[1]->szLastName = L"Smoe";
uaListBoxPtrArray[1]->szAccountName = L"jsmoe";
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