Re: [boost] Re: Re: Threads Rewrite?

From: Stefan Seefeld (seefeld_at_[hidden])
Date: 2004-07-28 19:21:37

Tonko Juricic wrote:

> A stumbling block in my case is understanding how can
> your code be executed by a non-boost thread unless, at
> some level, you explicitly make it possible.

yes. A typical example is where you are writing application
code (with boost::thread) that hooks up with a multi-threaded
middleware (CORBA, say), i.e. your code provides callbacks
that this third-party backend calls into.

> So, if I didn't completely miss the point, TLS cleanup
> for non-boost threads is there to spare the programmer
> from having to analyze complex scenarious and calling
> sequences which may lead to a non-boost thread
> visiting the 'unsuspecting' method on your object.

Think about a logging library you are writing. For each
log message you want to write out an id associated with
the current thread. To do that you define a (global)
thread_id variable, and you want that to have a different
value for each executing thread.
Thus, you provide a function 'get_thread_id()' that will
allocate the variable on the thread-local heap the first
time it is called (per thread, of course). But how is it
cleaned up ? You get the idea...

Stefan