How to programmatically identify the thread ID printed in GDB

Question

I am trying to debug an application written in c++, compiled for an ARM based processor running linux.

When the application intermittently crashes, it stops at a certain thread and I assume that thread is where is the fault is (segmentation fault).

My problem is, I am having trouble identifying WHAT this thread is. I see that the following printed in eclipse when GDB is running.

What are the numbers underlined in blue and is there a way for me to access them programmatically, so that I know where to look in the code ?

enter image description here

Gdb can display thread names, check [link](https://sourceware.org/gdb/onlinedocs/gdb/Threads.html) for more info — Selçuk Cihan, Apr 20 '15 at 14:42

score 4 · Accepted Answer · edited May 23 '17 at 11:45

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In addition to @Heshan Perera answer.

You can also access the thread id which is the bigger number, inside your program

UNIX:

#include <sys/syscall.h>
syscall(SYS_gettid);

WINDOWS: (Not tested)

#include <windows.h>
GetCurrentThreadId();

edited May 23 '17 at 11:45

Community

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answered Apr 20 '15 at 16:22

WaeCo

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score 0 · Answer 2 · answered Apr 20 '15 at 15:05

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Based on this link posted by @Selcuk Cihan in the comment above, the first number within square brackets is an integer identifier assigned by GDB itself and the other is the SysTag assigned to the thread.

answered Apr 20 '15 at 15:05

Heshan Perera

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score 0 · Answer 3 · answered Jan 20 '17 at 09:36

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A better solution, if you're on Linux/gcc, is to actually give a descriptive name to the thread with pthread_setname_np. gdb will then use this name when hitting breakpoints, and so on. Note that this is a GNU extension to pthreads.

answered Jan 20 '17 at 09:36

EML

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How to programmatically identify the thread ID printed in GDB

3 Answers3