[boost] Re: Problematic inclusion of "pthread.h".

From: Markus Schöpflin (markus.schoepflin_at_[hidden])
Date: 2004-10-06 03:02:21

Jonathan Wakely wrote:

> On Tue, Oct 05, 2004 at 06:23:46PM +0200, Markus Schöpflin wrote:
>> 
>> The native compiler (toolset tru64cxx65) doesn't define _REENTRANT and
>> things seem to work out correctly.
> 
> If you use the tru64cxx65 equivalent of -pthread then I bet it _does_ 
> define _REENTRANT. The problem is that GCC was changed so that
> _REENTRANT is defined whether or not -pthread is used.

Yep, you're right. -pthread toggles the definition of _REENTRANT on cxx.
Interestingly it does this also with gcc when you look at the output of the
predefined macros of the compiler.

>> GCC's include files OTOH unconditionally define _REENTRANT before
>> including "pthread.h" which forces boost to also include "pthread.h",
>> if I understand things correctly.
> 
> Near enough, yeah.
> 
>> But reentrant is not defined at the point where "pthread.h" is
>> included which leads to the problem described.
> 
> Why not though, that's the question.
> 
> Since <boost/config.h> is included first by shared_ptr.hpp, that should 
> include <string> (or any other libstdc++ header) which should define 
> _REENTRANT and therefore it should be set when we come to pthread.h
> 
> If you want to, run the test with the GCC flag -save-temps and send me
> the preprocessed .ii file, and I'll get medieval on it.

Will do in private mail. Thanks in advance.

Markus