[Python-Dev] Warning about use of long double (original) (raw)

[Python-Dev] Warning about use of long double - what's the correct approach?

Michael Hudson mwh@python.net
08 Oct 2002 10:58:26 +0100

Skip Montanaro <skip@pobox.com> writes:

When building from CVS head, I get this warning for each file compiled:

On Mac OS X, right?

gcc -c -DNDEBUG -g -I. -I../Include -DPyBUILDCORE -o Objects/rangeobject.o ../Objects/rangeobject.c In file included from ../Include/Python.h:70, from ../Objects/rangeobject.c:3: ../Include/objimpl.h:252: warning: use of `long double' type; its size may change in a future release ../Include/objimpl.h:252: warning: (Long double usage is reported only once for each file. ../Include/objimpl.h:252: warning: To disable this warning, use -Wno-long-double.)

The culprit is the long double alignment field in: /* GC information is stored BEFORE the object structure. */ typedef union gchead { struct { union gchead *gcnext; union gchead *gcprev; int gcrefs; } gc; long double dummy; /* force worst-case alignment */ } PyGCHead; I don't know what the best way to fix this is. Should I look at making configure add -Wno-long-double in the proper situations or should that alignment field be something else in situations where the use of long double would generate a warning?

I thought that's what configure already did:

case $ac_sys_system in
Darwin*)
    OPT="$OPT -Wno-long-double -no-cpp-precomp";;
esac

If I've guessed wrong and you're not on OS X, give us some help :)

Cheers, M.

-- I'm sorry, was my bias showing again? :-) -- William Tanksley, 13 May 2000