Identical code on the same machine, different binaries producing different results.

The only variable is the binaries?

Conclusion: One of the binaries is broken.

Both my binaries are built on top of Perl 4 (same version). Is there an Linux library (maybe math) that Perl calls to evaluate pack? like libm or so?

I don't have sources for Perl4, but I do not see any reason why any libraries would be involved. Most of what pack & unpack do is bit and byte manipulations.

If you were using Perl5, I would suggest using perl -V to look for build/configuration changes, but never having used Perl4, I am not even sure if it had this switch.

Another possibility that would be revealing (in Perl5 at least), would be to dump and compare the key/value pairs of %Config. Here I've picked out a few of the possibly relevant ones:

perl -MConfig -wle" print $k, ' => ', defined $v ? $v : '[n/a]' while 
+($k,$v) = each %Config"

archlibexp => c:\Perl\lib
archname => MSWin32-x86-multi-thread
cc => cl
ccflags => -nologo -Gf -W3 -MD -Zi -DNDEBUG -O1 -DWIN32 -D_CONSOLE -
cppflags => -DWIN32
dlsrc => dl_win32.xs
dynamic_ext => Storable Encode XS/Typemap MIME/Base64 IO B/C Devel/P
...
byteorder => 1234
...
i16size => 2
i16type => short
i32size => 4
i32type => long
i64size => 8
i64type => __int64
i8size => 1
i8type => char
...
intsize => 4
issymlink =>
ivdformat => "ld"
ivsize => 4
ivtype => long
...
lddlflags => -dll -nologo -nodefaultlib -debug -opt:ref,icf  -libpath:
+"c:\Perl\lib\CORE"  -machine:x86
ldflags => -nologo -nodefaultlib -debug -opt:ref,icf  -libpath:"c:\Per
+l\lib\CORE"  -machine:x86
...
loclibpth => /usr/local/lib /opt/local/lib /usr/gnu/lib /opt/gnu/lib /
+usr/GNU/lib /opt/GNU/lib
longdblsize => 10
longlongsize => 8
...
perllibs =>   oldnames.lib kernel32.lib user32.lib gdi32.lib winspool.
+lib ...
...
[download]

---

Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.

Lingua non convalesco, consenesco et abolesco. -- Rule 1 has a caveat! -- Who broke the cabal?

"Science is about questioning the status quo. Questioning authority".

The "good enough" maybe good enough for the now, and perfection maybe unobtainable, but that should not preclude us from striving for perfection, when time, circumstance or desire allow.