People who think that case X cannot be debugged without printf often don't know the features of their debugger. I.e. look at several of the comments which seem to miss that you can:

- Remote debug.

- Use conditional breakpoints.

- Use breakpoints to trigger commands, e.g. log values, enable other breakpoints, etc. instead of stopping. execution.

- Debug multi-threaded code.

- Disassemble a fragment.

I have a bunch of (36 if you're counting :) short videos and blog posts introducing the advanced features of GDB: https://undo.io/resources/gdb-watchpoint/

Just yesterday I gave a talk at MeetingC++ in Berlin on debugging multithreaded code. It's amazing how few developers know anything beyond the very basic of their debugger. If all you know is print, break, continue, next and then you dismiss the debugger as "not very useful" then you've not made a judgement based on information but on initial reaction.

Oh thanks, I know about that and agree. I did not understand the point about doing debugging in containers.

But I think I understand now. I guess they only debugging a program that is running in a container.

Many people believe that a debugger won't work in their specific scenario, but often they are wrong; debugger can connect across network boundaries or into other processes that weren't launched by the IDE