Re: [Boost-users] [spirit] thread safety / lock freedom

From: João Abecasis (jpabecasis_at_[hidden])
Date: 2006-04-13 19:37:47

Hi!

Tim Blechmann wrote:
> i'm currently looking into the spirit library to create a parser ... it
> seems to be threadsafe, but it's using thread locks.
> is it possible to use the library in a lockfree manner? can i be sure,
> that there will be no lock misses, when i'm not sharing parsers between
> the threads?

Regarding Spirit, it has two different thread-related modes of 
operation. The default one is thread-unsafe because of static data used 
internally by Spirit. If you use Spirit from a single thread at a time 
you'll be safe even in a multithreaded environment, however.

The thread-safe mode is triggered by defining BOOST_SPIRIT_THREADSAFE. 
When this is defined, mutexes (and other Boost.Threads utilities) are 
used to ensure thread-safe initialization and sharing of static data 
across threads.

If you're NOT sharing parsers across threads or if you DO manage locking 
yourself you can skip the definition of BOOST_SPIRIT_THREADSAFE.

If you (or anyone else, for that matter) will be trying 
BOOST_SPIRIT_THREADSAFE be sure to try the patch I posted here,

     http://article.gmane.org/gmane.comp.parsers.spirit.general/10472

and report any bugs you come across ;-)

Best regards,

João