Print thread ID in log messages

[gavv]

Problem

It would be convenient to include integral thread identifier in log messages.

Currently messages look like this:

13:36:34.803 [dbg] roc_sndio: initializing pulseaudio backend

and with thread ID they should look like:

13:36:48.977 [7843] [dbg] roc_sndio: initializing pulseaudio backend

This thread ID can be used to distinguish threads, and, at least on Linux, to find these threads in ps/top and to send signals to them.

Solution

We can use syscall(SYS_gettid) on Linux and pthread_getthreadid_np() on OSX and (in future) on BSD. Both function are non-portable.

Steps:

• Add target_linux and target_bsd to SConstruct. target_linux should be enabled if platform is linux or android. target_bsd should be enabled if plarform is darwin.

• Add core::format_tid(), similar to core::format_time(). It should have two implementations: src/modules/roc_core/target_linux/roc_core/format_tid.cpp (using SYS_gettid) and src/modules/roc_core/target_bsd/roc_core/format_tid.cpp (using pthread_getthreadid_np).

• Use core::format_tid() in core::Logger::print().

[dshil]

@gavv, what about using uv_thread_self()?

[gavv]

@dshil it's portable, but, just like pthread_self(), it returns an opaque handle that is not an integral type. It can't be printed, or used to find the thread in ps/top, or used to to send a signal to the thread.

[gavv]

Assigned to @RohanK99.