使用 eclipse cdt 调试多线程应用程序

Question

I am developing multithread application with c++ using eclipse cdt. I need to debug my code, i have tried to write to console by using printf but it is not very useful. How do i debug my multithread code?

Answer 1

It depends on what you're looking for, but debugging multithreaded applications can be very similar or extremely dissimilar to debugging single threaded apps.

First, some example methods you can still use:

1. Use breakpoints with an IDE
2. Use various solid relevant debugging tools such as Valgrind. Here's a link to a good article full of tools:C++ TUTORIAL MULTI-THREADED PROGRAMMING DEBUGGING - 2020
3. Output to separate files OR use locks if outputting to the same file/stream (not recommended but will touch on this)

I assume the issue you're running into here with printf is that it's like multiple threads writing to the same file- it's a race condition for what output you'll see on the screen. I'd personally still recommend using a tool like valgrind if you're running into a multithreaded error, but if you'd like to continue using simple console output, try...

• Write to different files instead of to standard output/the console
• Use a lock/mutex to assure only 1 thread is writing to standard output at the same time (which could mask race condition or such issues due to adding in blocking for that lock before printing)
• A more so wild idea: Share state (via a lock to avoid multiple threads reading or writing to the data at the same time) or otherwise return output to a single thread that's dedicated to writing out your debug info. Similar to the above but slightly different in implementation and useful if you'd like to design in a dedicated multithreaded log system for future improvements

All in all, the exact tool you should be using here depends on the exact issue you're facing and thus no strong recommendations just yet. Please apply the tools above (including breakpoints in Eclipse) to suit your situation.