Debugging multithreaded programs in gdb

So, like in above example we have 4 active threads. Each thread has an assigned ID, which is visible in first column. In non multi threading applications there is only one thread i. But in multi threading applications, as there are many threads and each threads has its own stack. Now what if want to inspect stacktrace of all the threads at same point? To display the stack trace of all the threads use following command gdb thread apply all bt It will display the stack trace of all the active threads.

Your email address will not be published. For some multi-threaded targets, GDB supports a further mode of operation, called non-stop mode , in which you can examine stopped program threads in the debugger while other threads continue to execute freely.

Versions of GDB prior to 7. The variable gdb-non-stop-setting determines whether Emacs runs GDB in all-stop mode or non-stop mode. The default is t , which means it tries to use non-stop mode if that is available. If you change the value to nil , or if non-stop mode is unavailable, Emacs runs GDB in all-stop mode. Shown below is partial output of a GDB run of the racecond program with 3 threads run 3 , showing examples of GDB thread commands in the context of a GDB debugging session.

When debugging multithreaded programs, the GDB user must keep track of which threads exist when issuing commands. For example, when the breakpoint in main is hit, only thread 1 the main thread exists. As a result, the GDB user must wait until threads are created before setting a breakpoint for only a specific thread this example shows setting a breakpoint for thread 4 only at line 77 in the program.

Dive Into Systems 3. C Debugging Tools 3. Debugging Multi-threaded Programs. Debugging Multithreaded Programs with GDB Debugging multithreaded programs can be tricky due to the multiple streams of execution and due to interactions between the concurrently executing threads.