AIX status

[David Edelsohn]

>>>>> Phil Edwards writes:

Phil> WRT -lpthread...

Phil> Doesn't libtool track dependancies?  (Assume for argument's sake that
Phil> libtool would work on AIX "as well" as it does on Linux today.)  If we're
Phil> using libtool properly, we should be able to tell it to supply -lpthread
Phil> when needed, automatically.

	Are you referring to mknumeric_limits or general pthread support
when compiling the library?  GCC normally supplies -lpthread itself;
however, mknumeric_limits invokes GCC with -nodefaultlibs which disables
the normal library processing.  There is no problem when compiling and
linking the library itself and no need to introduce libtool.

	mknumeric_limits explicitly links with libgcc.a and libc.a.  AIX
happens to need libpthread.a when configuring for pthreads.  Cygwin has
other dependencies.  I do not understand why this raises such attention.

Phil> The thread targets aren't for "posix under machine X,"
Phil> they're for entirely different kinds of threads.  If you want to use posix
Phil> threads, then we need to make --enable-threads=posix work properly, rather
Phil> than introducing a "synonym wrapper".  IMO.

	I would be happy to collaborate with anyone to allow
--enable-threads=posix to "work properly" on AIX given AIX's requirements.
Some of the previous comments lead me to believe that "posix" support
should not be cluttered with AIX's needs, so I was trying to keep the
changes localized to configure and not affecting common files and
configure case.

	Can the pthreads case for configure include a special set of AIX
tests for when to use threads-posix.h and threads-no.h?

	Can threads-no.h and threads-posix.h be merged and wrapped by
_GLIBCPP_USE_THREADS after including c++config.h to choose which set of
definitions?

	AIX needs to include pthread.h and define the v3/libio threads
symbols when the -pthread compile/link option is present and not reference
those symbols when the -pthread compile/link option is absent.  AIX does
not (cannot) provide weak, no-op versions of the symbols when the option
is absent.

	Some avenue needs to be left open for platforms with this type of
requirement.  I would be happy for anyone to suggest viable alternatives.

David