[Patches] [ python-Patches-968728 ] Py_HUGE_VAL HUGE_VAL HUGE undefined

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Patches item #968728, was opened at 2004-06-08 08:48
Message generated for change (Comment added) made by cross
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Category: Core (C code)
Group: Python 2.3
Status: Closed
Resolution: Wont Fix
Priority: 5
Submitted By: Michael Schloh von Bennewitz (michaesc)
Assigned to: Nobody/Anonymous (nobody)
Summary: Py_HUGE_VAL HUGE_VAL HUGE undefined

Initial Comment:
In Python 2.3.4 (as well as the trunk revision on CVS), Py_HUGE_VAL 
is conditionally defined as HUGE_VAL. On at least Solaris 10 x86 and 
Solaris 10 SPARC, this causes a build failure.

I'm ashamed to say that I wasn't able to 100% diagnose this problem (I 
didn't have time). My first guess was that somehow HUGE_VAL was not 
getting properly defined on Solaris 10 due to its rewritten 
/usr/include/iso/math_iso.h file (now conditionally defining HUGE_VAL 
depending on a _STDC_C99 and _XOPEN_SOURCE definition).

Because I noticed that the identifier HUGE is unconditionally defined 
on Solaris 10 and seemingly all earlier Solaris releases, I tried using 
that instead and the build problem disappeared.

You can make your own conclusion as to whether my fix is correct, or if 
there is a better way to solve this problem. There may be a faulty 
assumption made by configure or in some Makefile of how the compiler 
is being used, or maybe python depends on a certain GCC release.

  CC: GCC 3.4.0
  CXX: GCC 3.4.0
  CFLAGS:   -O2 -pipe
  CXXFLAGS:   -O2 -pipe
  CPPFLAGS: None 
  Make:     GNU Make 3.80
  LDFLAGS:  None

  mich at dev:/tmp/Python-2.3.4$ ./configure --prefix=/cw
  checking MACHDEP... freebsd4
  checking EXTRAPLATDIR... 
  checking for --without-gcc... no
  checking for --with-cxx=<compiler>... no
  ...

The OpenPKG Python package and patch:
http://cvs.openpkg.org/dir?d=openpkg-src/python
http://cvs.openpkg.org/rlog?f=openpkg-src/python/python.patch

Lots of luck, and thanks for maintaining Python.

Regards,
Michael, OpenPKG
http://www.openpkg.org/


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Comment By: Chris P. Ross (cross)
Date: 2004-12-23 18:40

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Oops.  My bad.  I failed to mention that I'm using gcc 3.4.x
on Solaris 10.   I assume those options are for the Forte
suite (or whatever they're calling it now).

Hmm.  I wonder how to tell sun that they're header isn't
compliant?  I wonder if it fails in the same way with Forte?

I should try to find out...  It *is* a beta OS after-all.  :-)

Thanks!


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Comment By: Tim Peters (tim_one)
Date: 2004-12-23 18:09

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>From C99:

"""
The macro

HUGE_VAL

expands to a positive double constant expression, not 
necessarily representable as a float.

...

(footnote) HUGE_VAL, HUGE_VALF, and HUGE_VALL can be 
positive infinities in an implementation that
supports infinities.
"""

Of course a function pointer is not "a positive double 
constant expression", so doesn't meet the standard's 
requirements.

Some Googling suggested that the "-Xc or -Xa compliation 
options" may be needed to get standard behavior on Solaris, 
but that's just hearsay and I really have no idea.  Reports of 
HUGE_VAL creating compilation problems on Solaris for other 
projects are also easy to find.

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Comment By: Chris P. Ross (cross)
Date: 2004-12-23 17:43

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Hi.  I found this today as well.  However, a little research
shows that what it's defined to (__builtin_huge_val) is
actually a function pointer, not a number.  So, if I changed
Py_HUGE_VAL to be #def'd to HUGE_VAL(), it worked just find
on my Solaris 10 machine.

What does the c89 and c99 spec say that HUGE_VAL macro
should be?  A number?  Or is having it be a function
reference legal?



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Comment By: Hye-Shik Chang (perky)
Date: 2004-07-17 14:05

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This doesn't look like a bug in Python per Tim's comment.

(Reviewed by Seo Sanghyeon and me at KLDP CodeFest)

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Comment By: Tim Peters (tim_one)
Date: 2004-06-08 19:02

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I don't see a reason to call this a Python bug.  The C89 and 
C99 standards both require that math.h supply the HUGE_VAL 
macro.  If the compilation system you're using doesn't do so, 
it's a bug in that system, and should be fixed there.  Python 
doesn't ask for much, but does require an ANSI C compiler.

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