Re: [boost] [threads] Future directions (Was: TR2 and C++0x heads up)

From: Ion Gaztañaga (ion_g_m_at_[hidden])
Date: 2005-04-24 13:58:47

Peter Dimov wrote:

>>Use aligned_storage<> and placement new.

 Sorry, I didn't know what aligned_storage was for, boost is really huge. 
I've seen it uses a union using alignment information from other boost 
tools. Doing an placement new invalidates automatic destructor, so it sounds 
to me like the famous ugly pimpl hack to avoid dynamic memory and header 
dependences, based on max_align. Anyway, it is true that dynamic memory is 
the best way to make thread lifetime independent from boost::thread object's 
lifetime, so maybe in those special systems, a singleton memory pool should 
be used for this, if "new" function is not available. What I don't know if 
that singleton lifetime can lead to problems because I don't know if threads 
must exit before static object destructors are called, but this is another 
topic. I think embedded C++ should be taken in care because C++ is used a 
lot in this area (for example, eCos embedded OS is written in C++ with a  C 
wrapper API). The C++ phylosophy ("you don't pay for what you don't use") is 
very nice in these systems, if you know what is happening behind the scenes 
with C++ (inheritance, constructor/destructors, etc...).

 It would be nice to have some brainstorming regarding boost threads if it 
is possible. I don't know if C++0x wants only to include basic functionality 
in threads but I think developers are waiting for some more complex 
utilities, like thread pools.

Regards,

Ion