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by kevincox 1910 days ago
You said "click", I need to leave my keyboard.

Generally when I am coding I auto-run the tests on save. This means that to printf-debug I just add a message or two (and if I am coding I might already have a couple of useful ones lying around) and save. Then in less than a second I have a trace trough my program in the terminal. If I want to inspect a different variable I just add another print and run again.

With a debugger I need to kill my auto-run command, run the program, set breakpoints, type to see what variables I want to inspect, maybe switch stack frames, maybe step through a bit.

In my mind printf is like an automated debugger. I just put the info I want to see into the program and it does all of the printing for me. And when I find the problem I can just fix it and I am back to my edit-test cycle.

I'm not saying that there are no use cases for a debugger. For example I find variable-modification breakpoints very useful. As you mentioned if your edit-run cycle is slow then it may be faster to inspect a new variable in the debugger than adding another print statement. But when I just want to inspect values in my program I find printf sufficient and lower overhead. I'm sure part of my problem is that because I rarely use a debugger I am not as efficient, but I also think that printf-debugging is a very effective workflow for a wide variety of issues.

2 comments

You said "click", I need to leave my keyboard.

Every proper IDE has a keyboard shortcut for that though.

With a debugger I need to kill my auto-run command, run the program, set breakpoints, type to see what variables I want to inspect

This indeed falls under your 'part of my problem is that because I rarely use a debugger' statement. E.g you could set breakpoints before you save, use auto-debug instead (i.e. launch program under the debugger on save instead of just rnning it - without breakpoints there shouldn't be much of a difference unless it's one of those nasty multithreading bugs), add variables you want to see to the watch window. Or type them anyway if it's a one-time thing. Or use tracepoints. Etc.

I personally keep bouncing back and forth between debugger and printing. All depends on context, but it's definitely worth it getting to know both really well.

So basically tracepoints, without touching the program code.
But I'm already mucking with the program code most of the time so I'm not worried about touching it.