From: David Abrahams (dave_at_[hidden])
Date: 2006-08-31 08:35:06
Vladimir Prus <ghost_at_[hidden]> writes:
> On Thursday 31 August 2006 00:56, David Abrahams wrote:
>> Update of /cvsroot/boost/boost/tools/build/v2/tools
>> In directory sc8-pr-cvs3.sourceforge.net:/tmp/cvs-serv4741
>> Modified Files:
>> Log Message:
>> Fix QNX's dependency on pthread (which doesn't exist on those systems).
>> Clean up the comments a bit.
>> Index: python.jam
>> RCS file: /cvsroot/boost/boost/tools/build/v2/tools/python.jam,v
>> retrieving revision 1.30
>> retrieving revision 1.31
>> diff -u -d -r1.30 -r1.31
>> --- python.jam 25 Aug 2006 07:22:22 -0000 1.30
>> +++ python.jam 30 Aug 2006 20:56:26 -0000 1.31
>> @@ -139,22 +139,12 @@
>> switch [ os.name ]
>> - case SOLARIS : extra-libs = dl ;
>> - case OSF : extra-libs = ;
>> - case QNX* : extra-libs = ;
>> - case * : extra-libs = dl util ;
>> + case SOLARIS : extra-libs = pthread dl ;
>> + case OSF : extra-libs = pthread ;
>> + case QNX* : extra-libs = ;
>> + case * : extra-libs = pthread dl util ;
>> - # Depending on system, Python library is either static
>> - # or shared. When it's static, we need to add 'pthread'
>> - # to link line of all clients, otherwise we'll get
>> - # unresolved symbols. Same effect can be accomplished
>> - # by using <threading>multi on the client, but
>> - # that can have performance overhead, and is not really
>> - # necessary, as Python interface has nothing that's
>> - # affected by threading mode.
> I assume that this comment was deleted by mistake? It captures quite some
> discussion we had, so I'm about to put it back.
Hmm, I had some problems with it and it seemed out of place once I had
no special section just for -lpthread. It certainly is wrong even for
some platforms that use a static python library (QNX), and it seems to
incorrectly imply that there's only either a dynamic or a static
python library, but not both, on any given platform. Now that I look
at it, though, I realize that it does capture something useful. I
propose this replacement, above the switch:
# Provide system library dependencies for static Python libraries.
# Static libraries carry no library dependency information of
# their own that the linker can extract, so library dependencies
# have to be given explicitly on the link line of the client.
# package the information into the "python" target below.
# Even where Python itself uses pthreads, it never allows
# extension modules to be entered concurrently (unless they
# explicitly give up the interpreter lock). Therefore,
# extension modules don't need the efficiency overhead of
# threadsafe code as produced by <threading>multi, and we
# handle libpthread along with other libraries here.
Whew, _that_ took a long time to write!
-- Dave Abrahams Boost Consulting www.boost-consulting.com
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