[PD-dev] [ pure-data-Bugs-1788587 ] unpackOSC doesn't like typed floats

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Bugs item #1788587, was opened at 2007-09-05 18:01
Message generated for change (Comment added) made by zmoelnig
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Category: externals
Group: None
Status: Open
Resolution: None
Priority: 5
Private: No
Submitted By: IOhannes m zmölnig (zmoelnig)
Assigned to: Martin Peach (mrpeach)
Summary: unpackOSC doesn't like typed floats

Initial Comment:
unpackOSC does not decode an osc-message correctly that contains a floating-point number and typetags.
(see attached patch to trigger the bug)

the problem only occurs if compiled with strict-aliasing enabled (default on gcc>3.0 with optimization levels 2, 3, s), because unpackOSC uses pointer-casts for re-interpreting the data.

for information on this see:
http://mail.opensolaris.org/pipermail/tools-gcc/2005-August/000047.html

one way to prevent this problem is by adding the "-fno-strict-aliasing" to the CFLAGS.

unfortunately, osc comes without build-system so you cannot add this flag...

tested with: pd-0.40.1, pd-0.41test6 (linux x86)

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>Comment By: IOhannes m zmölnig (zmoelnig)
Date: 2007-09-05 18:04

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one more remark:
 neither the version in pd-extended nor matt wright's original "dumpOSC"
application usually exhibit this problems, as they use different compiler
flags.

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Comment By: IOhannes m zmölnig (zmoelnig)
Date: 2007-09-05 18:04

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a more generic solution for this problem is to use unions (as described in
the above-mentioned article) instead of pointer-casts.

the attached patch does this and it seems to fix the problem, it would be
nice if this could make it into osc (for the one single person who does not
use the pd-extended build-system)
File Added: unpackOSC.c.diff

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