I’m up to chapter 42 in the Linux e-book. The rest have gone very smoothly though I’m still unable to debug either on my Hyper-V Ubuntu or my Ubuntu running laptop. Both still have the same problem XDG_RUNTIME_DIR not set in the environment.

I’ve been reading up on that and it seems if you switch into root and the value of the environment variable $XAUTHORITY is blank then that is the problem.

My error logging is picking up problems with sound channels not playing. I think the problem is, when I hit the b key to make lots of asteroids explode, it uses up all available sound channels and there’s still explosions happening.  Not really a problem.

But to cap it all, there is a segmentation error happening with a core dump. A segfault which kills the program. But it’s not related to the sound problem. I’ve proved that by commenting out the entire PlayASound function. It now looks like this which I call the sound of silence.

void PlayASound(int soundindex) {
	//int success=Mix_PlayChannel(-1, sounds[soundindex], 0);
	//if (success == -1) {
	//	LogError2("Mix_PlayChannel failed to play audio sound #",SDL_ltoa(soundindex,buffer,10));
	//}
}

So without being able to run the program in a debugger, I’m forced to start putting in lots of logging calls and figure out where the segfault happens that way. It’s an effective way of finding bugs BUT it’s not the fastest! I have also enabled apport to try and get the crash files created in /var/crash so that may be a faster way forward.

Once I have fixed the segmentation fault, I’ll upload the fixed code to Github. It’ll be somewhere in the new code added between chapter 37 and chapter 42, to do with collision detection. Time to put on a deerstalker hat!