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[Bug libstdc++/39491] [4.4/4.5 regression] symbol __signbitl@GLIBCXX_3.4 in libstdc++ not exported anymore



------- Comment #12 from dave at hiauly1 dot hia dot nrc dot ca  2009-04-21 21:01 -------
Subject: Re:  [4.4/4.5 regression] symbol __signbitl@GLIBCXX_3.4 in libstdc++
not exported anymore

> At present glibc does not create an long double alias for the double __signbit
> function, but for the sake of correctness it probably should.

In my build of gcc 4.3.3 and also debian 4.3.2-1.1 (lenny), I see
the symbol __signbitl in libstdc++.so.6.0.10.  We also have
__signbitl@@GLIBCXX_3.4.

In libstdc++.a, I see:
signbitl.o:
00000000 T __signbitl

In 4.3, we had the function signbitl.c in libmath.  This was removed in 4.4.

Looking at the 4.3 implementation, I see that it assumes a 96-bit long double
format.  This is wrong for hppa-linux, but I think the signbit extraction
works because of the alignment of the long double value in the union.

Dave


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39491


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