Breaking out from generating windows in infinite loop

Question

In my program I made an obvious typo

for(int i = 0; i<mNoOfCores; i+3)

instead of

for(int i = 0; i<mNoOfCores; i++)

Unfortunately, in the loop I was generating QT5 windows. So my Ubuntu system was absolutely denied, I could only restart after power-on reset. (the mouse was responsive, and probably so was the keyboard, too.) Is there a better method? Or, in this way I can deny my OS from an application?

Its not really clear to me what you are asking. The better way is of course to avoid infinite loops (especially when you create windows inside that loop). — 463035818_is_not_an_ai, Mar 11 '16 at 12:37

score 1 · Answer 1 · edited May 23 '17 at 12:07

1

There is no way for compiler to inform you in advance about infinite loops. This is discussed at many places, here, here, here.

What you can do is use simple "double checks" to prevent yourself from hanging the OS. Example:

int totalNoWindowsCreated = 0; // keep track of windows created OK
for(int i = 0; i<mNoOfCores; i+3)
{
  // Create window  
  totalNoWindowsCreated++; // If created OK
  assert(("Bug !", totalNoWindowsCreated <= mNoOfCores)); // Check
}

UPDATE: Of course, you can make mistake in assert condition, in that case, just take a break and drink coffee :).

edited May 23 '17 at 12:07

Community

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answered Mar 11 '16 at 12:53

vcp

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Shouldn't the assert check if `totalNoWindowsCreated < mNoOfCores`? – Alfie J. Palmer Mar 11 '16 at 13:00
2

@AlfieJ.Palmer so fast a double check can turn into a double bug ;) – 463035818_is_not_an_ai Mar 11 '16 at 13:01
Sorry for the misunderstanding. I do not want to protect myself programmatically. I wonder if there exists some hotkey combination, which allows kill that wild program. – katang Mar 11 '16 at 15:24
`Ctrl + Alt + Esc`, for details see this Q&A : http://askubuntu.com/questions/104903/how-do-i-kill-processes-in-ubuntu – vcp Mar 11 '16 at 17:38

Breaking out from generating windows in infinite loop

1 Answers1