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376 points turrini | 1 comments | | HN request time: 0s | source
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rkharsan64 ◴[] No.42146864[source]
On a general note, I would recommend any new (and experienced!) programmers to master the debugging tools of their ecosystem. I've seen countless experienced developers use printf-based debugging and waste hourse debugging something which could've been easily figured out by setting a breakpoint and stepping through your code. This is also a good way to understand code you're unfamiliar with.

This is one area where I believe a GUI tool is so much better: I can hover over variable names to view their values, expand and collapse parts of a nested structure, edit values easily, and follow execution in the same environment I write my code in.

Sure, it doesn't help much for some scenarios (one I've heard people mention is multithreaded code, where logs are better?), but for most people it's not that far from a superpower.

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mpweiher ◴[] No.42147101[source]
Interesting.

My experience is the opposite: I see developers waste hours stepping through their code a line at a time when a few judiciously placed logs (printfs() are fine, but we can do better) would have told them exactly what they needed in a jiffy.

If you have a fairly shallow bug, that is a single point in your code that always behaves incorrectly, then I find debuggers reasonably effective.

But most of the bugs that I see aren't that shallow, with code misbehaving when the context is just so and perfectly fine otherwise. In those cases, I need to see lots of different invocations and their context. The debugger is like trying to drink the information ocean I need through a straw. A mostly plugged straw.

I wonder what makes our experiences so different? Do you unit test a lot? Particularly with TDD? I am guessing that this practice means I just don't get to see a lot of the bugs that a debugger would help me with.

(And it doesn't mean I never fire up the debugger. But it is fairly rare).

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BearOso ◴[] No.42147930[source]
Inserting a breakpoint is just as easy as a printf, and as long as you're still using a debugging build, you don't have to recompile. With the printf you might not have considered all the variables you need, so you have to go back, insert, and recompile. With a breakpoint you can inspect the contents of anything at that scope, and even see what the code flow is with that given state. You can even save a core dump to go back to later.

You can also script breakpoints to output the info you want and continue, giving you your information ocean.

Basically, a debugger is a more efficient and powerful tool. In the one situation where you're not skilled with a debugger feature, a printf can be quicker than having to learn, but it's objectively worse.

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1. corysama ◴[] No.42148511[source]
You can insert and remove breakpoints while running. You can inspect variables the instant you realize they might be relevant.

During my long career, I’ve always been told “You should know you code well enough that a few well placed printfs is the most you’ll need to understand a bug”.

But, most of my career has been spent debugging large volumes of code written by other people. Code I’ve never seen before and usually will never see again.

A debugger making a 10X productivity difference for me is no joke.