[Discuss-gnuradio] Proper use of scoped_lock in out-of-tree module?

[Monahan-Mitchell, Tim]

I see different use cases of this in the gnuradio tree, like:

gr::thread::scoped_lock guard(d_mutex);

gr::thread::scoped_lock l(d_mutex);

gr::thread::scoped_lock lock(d_setlock);

As well as variances of whether the mutex variable is declared in a header 
file...

Could someone lend some kind words on what is recommended (at least for GR 3.7)?

Thanks,
Tim