Re^3: Negative zero from a multiplication by a zero?

I've reproduced it on two (out of two) linux boxes, one a 64bit machine.

$ perl -e 'for (-2.0,-1.9,-1.5,-1.1,-1.0,-0.9,-0.5,-0.1,-0)
 {$v = $_ * 0; printf("%5s -> %2s,%.100e\n",$_,$v,$v)}'
   -2 ->  0,0.00000000000000000000000000000000000000000000000000000000
+00000000000000000000000000000000000000000000e+00
 -1.9 -> -0,-0.0000000000000000000000000000000000000000000000000000000
+000000000000000000000000000000000000000000000e+00
 -1.5 -> -0,-0.0000000000000000000000000000000000000000000000000000000
+000000000000000000000000000000000000000000000e+00
 -1.1 -> -0,-0.0000000000000000000000000000000000000000000000000000000
+000000000000000000000000000000000000000000000e+00
   -1 ->  0,0.00000000000000000000000000000000000000000000000000000000
+00000000000000000000000000000000000000000000e+00
 -0.9 -> -0,-0.0000000000000000000000000000000000000000000000000000000
+000000000000000000000000000000000000000000000e+00
 -0.5 -> -0,-0.0000000000000000000000000000000000000000000000000000000
+000000000000000000000000000000000000000000000e+00
 -0.1 -> -0,-0.0000000000000000000000000000000000000000000000000000000
+000000000000000000000000000000000000000000000e+00
    0 ->  0,0.00000000000000000000000000000000000000000000000000000000
+00000000000000000000000000000000000000000000e+00

$ perl -v
This is perl, v5.8.8 built for i486-linux-gnu-thread-multi
...

$ uname -a
Linux fmdev10 2.6.24-etchnhalf.1-686 #1 SMP Tue Dec 2 07:56:33 UTC 200
+8 i686 GNU/Linux
[download]

(Debian build)

Comment on Re^3: Negative zero from a multiplication by a zero? Download Code

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Re^4: Negative zero from a multiplication by a zero? by Marshall (Canon) on Jun 09, 2009 at 18:13 UTC
I don't know what to say about this. It is weird to be sure! I have a 32 bit MS box. `C:\TEMP>perl -v This is perl, v5.10.0 built for MSWin32-x86-multi-thread (with 5 registered patches, see perl -V for more detail)` [download] Update: did a uname -a `C:\TEMP>uname -a CYGWIN_NT-5.1 cobra 1.5.25(0.156/4/2) 2008-06-12 19:34 i686 Cygwin` [download]	[reply] [d/l] [select]
Re^5: Negative zero from a multiplication by a zero? by ikegami (Patriarch) on Jun 09, 2009 at 18:26 UTC
Again, not all machines and libraries support negative zeroes. Perl lets the underlying layers handle this, so the results won't be the same on all machines.	[reply]