In working on getting a 64-bit Python to build and pass
the test suites on a Itanium 2 system running HP-UX 11,
there were two major issues that needed to be resolved:

- on ia64 HP-UX, unistd.h does not define
_POSIX_THREADS and therefore Python/thread.c was not
including thread_pthreads.h even though enough of the
posix threading API is available to support threads in
Python.

- isnan() was not being called to check floating point
numbers and math.sqrt(-1) would not throw a ValueError.


The attached patch make the following changes:

- modifies Python/thread.c to check for __hpux and
_SC_THREADS and if they're defined, then define
_POSIX_THREADS.

- modifies Include/pyport.h to check for __hpux and
__ia64 in the macro that defines _Py_SET_EDOM_FOR_NAN.

- modifies Readme to include details on how to build a
64-bit version of Python on a HP-UX based Itanium 2 system.

The patch file was created by running:

    cvs diff -c | tee ~/hpux_ia64_port.patch

from python/dist/src on a current CVS tree.


The current Readme also states that there is
optimization problems when building Python on an ia64
based HP-UX system using HP's C compiler. I have not
found this to be a problem. Should this note be removed
or marked as out of date?

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The patch looks good, but I have one comment:
it would be better if the user would not have to specify
flags explicitly. Python should build out of the box on the
platform, with not having to set environment variables.
Ideally, it should built forall of the most likely
configurations, i.e. c89/aCC and gcc, both 64 bits (I guess
nobody would want to build an ia32 binary even if this is
possible).

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I will work to check this in. I have to get the contribution
agreement reviewed by ESI management first.

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Checked into HEAD and 2.4 branch, in time for 2.4.2.

We didn't get to the automatic detection feature that Martin
requested; sorry.

We (Elemental Security) have mailed a contributor agreement
to the PSF.