After some digging it turned out to be a problem with locking. A mutex was never unlocked when returning in the exception handler. This was very strange as the unlocking should be done by the MutexLocker destructor.

I was able to reproduce the problem with a simple test program so I concluded that it was indeed a compiler bug and reported it: Destructor not called when returning in exception handler.

Not every day you get to find a compiler bug…

Dell’s Enhanced Multimedia USB Keyboard

Last week wasn’t one of my most productive weeks. Instead of working on my thesis, I created a small utility to make it possible to use the volume knob on Dell’s Enhanced Multimedia USB Keyboard under Linux. Not because I needed it, but because it didn’t work (and my other option was writing).

Anyway, if you’d like to check out the program (it’s named knob btw), you’ll find it on my self-entitled wiki WikiErik (yeah I know, the name sucks. But that’s how far my imagination goes when it comes to names).

Update:
As some of you have noticed, WikiErik is no longer available. But the code is still available. Point your browser to git.ejohansson.se and the project dellknob.git. Or clone it by running

git clone git://git.ejohansson.se/dellknob.git

Update 2:
Added a README with the contents from WikiErik.

First: “the named return value extension”. The idea is to avoid creating a temporary variable that’s assigned a value and then returned by value, thus creating an unnecessary copy. A small example:

std::list<int> foo(int j) return l();
{
  l.push_back(j);
}

This example will create just one list and append j to that. Without this extension a local list needs to be created, j appended to that and the copy constructor invoked when returning. This extension is deprecated in g++ 3.3 and removed in g++ 4.0.

My other example is the “min and max operators”. No, this is not about min and max macros nor the std::min and std::max functions. This is the min and max operators.

int min = x <? y;
int max = x >? y;

There is of course also a short-hand version for assigning one of the variables the smallest (or biggest) value of the two.

x <?= y;
x >?= y;

They are all deprecated in g++ 4.0.