Too memory used by the stack

[RIC63]

Hi everyone
I use VS Community 17.8.3 on a Hp Pc i7-9700 32Gb Ram W10pro 64

compiling the attached code I received a warning with code C6262:
"The function uses '4321508' bytes of stack. It is recommended to move some data to the heap."
The program crashed so I set the value you see in the image and now the program runs but it takes more than an hour to analyze 21000KB of text files

Does anyone have any suggestions for further settings or code modifications to optimize everything ?

Thank you

[2kaud]

The sizes of the used arrays are large. That's why it's exceeding the stack limit as these are allocated on the stack. Probably the easiest way to allocate these off the stack is to make them global rather than local to main(). Move the lines starting with const int nGroup and ending with int r5data to above int main(). These variables won't then be allocated on the stack and you shouldn't then need to change the stack dimensions.

Try putting a cout statement before while (ifs >> buf[0]) to display a message and see how long it takes to show the message and then how long to finish the program. This could give some indication as to which part of the program is taking the long time to complete.

[RIC63]

Hi 2kaud

thanks for your suggestion, I'll try to modify the code as you told me and I'll update you,

Thanks again

[alexsokolek]

You can also allocate your arrays on the heap. Create pointers in your stack (the automatic area in your braces) and then call new to allocate space. Don't forget to check for NULL on the return from new and also to delete (delete or delete[]) the array when you are done.

You can check for memory leaks by adding the following to your program at the beginning...

	// Setup to check for memory leaks. (Debug only.)
	#ifdef _DEBUG
	_CrtMemState sOld;
	_CrtMemState sNew;
	_CrtMemState sDiff;
	_CrtMemCheckpoint(&sOld); //take a snapshot
	#endif // _DEBUG

and the following code at the end of your program...

	// Check for memory leaks. (Debug only.)
	#ifdef _DEBUG
	_CrtMemCheckpoint(&sNew); //take a snapshot 
	if (_CrtMemDifference(&sDiff, &sOld, &sNew)) // if there is a difference
	{
		MessageBeep(MB_ICONEXCLAMATION);
		MessageBox(NULL, _T("MEMORY LEAK(S) DETECTED!\n\nSee debug log."), szTitle, MB_OK | MB_ICONEXCLAMATION);
		OutputDebugString(L"-----------_CrtMemDumpStatistics ---------\n");
		_CrtMemDumpStatistics(&sDiff);
		OutputDebugString(L"-----------_CrtMemDumpAllObjectsSince ---------\n");
		_CrtMemDumpAllObjectsSince(&sOld);
		OutputDebugString(L"-----------_CrtDumpMemoryLeaks ---------\n");
		_CrtDumpMemoryLeaks();
	}
	#endif // _DEBUG

Then you will get a message at the end if there are any leaks, and you can check the debug output in VS to see details.
Good luck.

[alexsokolek]

p.s. VS 2022 Community Edition is now at version 17.9.6. You might want to consider updating.

[2kaud]

Don't forget to check for NULL on the return from new

By default new raises an exception if an allocation issue arises. To have new return nullptr (nullptr in C++ not NULL) you need to indicate this by using std::nothrow. eg

auto p {new (std::nothrow) int};

if (p == nullptr) {
    // deal with new issue here
}

Better yet, use std::unique_ptr which is RAII so allocated memory will automatically be deleted when it goes out of scope.
https://en.cppreference.com/w/cpp/memory/unique_ptr
https://en.cppreference.com/w/cpp/me...tr/make_unique

[alexsokolek]

Instead of declaring and and allocating variable on the heap, using new and delete, you can declare them global, at file scope. You can also declare them static. If you do this to local function variables (normally allocated on the stack) they have file persistance.