ambiguous results from pack

[Ralph Crawford]

I'm trying to do development on a Linux laptop to port to Solaris.
However, I've run into a pack command that's returning incorrect results
on my laptop.

I'm using Perl 5.8.0 on all platforms. I've included the output of perl
-V also below because the problem seems to be so low level.

Here's the command...

perl -e 'print pack("I", 149);'|od -x

The correct response, which I get on most platforms, is this...

00000000 0095 0000
00000004

However, on my laptop, where it really matters, I'm getting this...

00000000 95C2 0000
00000004

I'd write this off as some weird endian problem, except that I'm getting
the incorrect results on an i386 based machine, and getting correct
results on 2 other i386 based machines, one Linux and one Cygwin.

Anyway, below is the output of perl -V. The first listing is the one
that's returning incorrect results, the rest are correct. I've changed
the hostname portion of the uname section, but otherwise these are verbatim.

Any help at all would be appreciated. If necessary I'll recompile Perl
on the laptop with the config parameters that'll correct the problem (if
I can find out what those are).

Thanks for your time.

Ralph

=======================================================================
Laptop Linux returning incorrect results.
=======================================================================
Summary of my perl5 (revision 5.0 version 8 subversion 0) configuration:
Platform:
osname=linux, osvers=2.4.20-6, archname=i686-linux
uname='linux laptop.somedomain.com 2.4.20-6 #1 thu feb 27 10:06:59
est 2003 i686 i686 i386 gnulinux '
config_args='-Uinstallusrbinperl -Dprefix=/data/gatekeeper/util
-des -Dcc=gcc'
hint=recommended, useposix=true, d_sigaction=define
usethreads=undef use5005threads=undef useithreads=undef
usemultiplicity=undef
useperlio=define d_sfio=undef uselargefiles=define usesocks=undef
use64bitint=undef use64bitall=undef uselongdouble=undef
usemymalloc=n, bincompat5005=undef
Compiler:
cc='gcc', ccflags ='-fno-strict-aliasing -D_LARGEFILE_SOURCE
-D_FILE_OFFSET_BITS=64 -I/usr/include/gdbm',
optimize='-O3',
cppflags='-fno-strict-aliasing -I/usr/include/gdbm'
ccversion='', gccversion='3.2.2 20030222 (Red Hat Linux 3.2.2-5)',
gccosandvers=''
intsize=4, longsize=4, ptrsize=4, doublesize=8, byteorder=1234
d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=12
ivtype='long', ivsize=4, nvtype='double', nvsize=8, Off_t='off_t',
lseeksize=8
alignbytes=4, prototype=define
Linker and Libraries:
ld='gcc', ldflags =' -L/usr/local/lib'
libpth=/usr/local/lib /lib /usr/lib
libs=-lnsl -lgdbm -ldb -ldl -lm -lc -lcrypt -lutil
perllibs=-lnsl -ldl -lm -lc -lcrypt -lutil
libc=/lib/libc-2.3.2.so, so=so, useshrplib=false, libperl=libperl.a
gnulibc_version='2.3.2'
Dynamic Linking:
dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags='-rdynamic'
cccdlflags='-fpic', lddlflags='-shared -L/usr/local/lib'


Characteristics of this binary (from libperl):
Compile-time options: USE_LARGE_FILES
Built under linux
Compiled at Nov 20 2003 15:24:36
%ENV:
PERL5LIB="/data/gatekeeper/prod/cur_ver/lib/perl:"
@INC:
/data/gatekeeper/prod/cur_ver/lib/perl
/data/gatekeeper/util/lib/perl5/5.8.0/i686-linux
/data/gatekeeper/util/lib/perl5/5.8.0
/data/gatekeeper/util/lib/perl5/site_perl/5.8.0/i686-linux
/data/gatekeeper/util/lib/perl5/site_perl/5.8.0
/data/gatekeeper/util/lib/perl5/site_perl

=======================================================================
Desktop Linux configuration returning correct results.
=======================================================================
Summary of my perl5 (revision 5.0 version 8 subversion 0) configuration:
Platform:
osname=linux, osvers=2.4.19-4gb, archname=i686-linux
uname='linux linux-host 2.4.19-4gb #1 fri sep 13 13:14:56 utc 2002
i686 unknown '
config_args='-Uinstallusrbinperl -Dprefix=/data/gatekeeper/util
-des -Dcc=gcc'
hint=recommended, useposix=true, d_sigaction=define
usethreads=undef use5005threads=undef useithreads=undef
usemultiplicity=undef
useperlio=define d_sfio=undef uselargefiles=define usesocks=undef
use64bitint=undef use64bitall=undef uselongdouble=undef
usemymalloc=n, bincompat5005=undef
Compiler:
cc='gcc', ccflags ='-fno-strict-aliasing -D_LARGEFILE_SOURCE
-D_FILE_OFFSET_BITS=64',
optimize='-O3',
cppflags='-fno-strict-aliasing'
ccversion='', gccversion='3.2', gccosandvers=''
intsize=4, longsize=4, ptrsize=4, doublesize=8, byteorder=1234
d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=12
ivtype='long', ivsize=4, nvtype='double', nvsize=8, Off_t='off_t',
lseeksize=8
alignbytes=4, prototype=define
Linker and Libraries:
ld='gcc', ldflags =' -L/usr/local/lib'
libpth=/usr/local/lib /lib /usr/lib
libs=-lnsl -ldl -lm -lc -lcrypt -lutil
perllibs=-lnsl -ldl -lm -lc -lcrypt -lutil
libc=, so=so, useshrplib=false, libperl=libperl.a
gnulibc_version='2.2.5'
Dynamic Linking:
dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags='-rdynamic'
cccdlflags='-fpic', lddlflags='-shared -L/usr/local/lib'


Characteristics of this binary (from libperl):
Compile-time options: USE_LARGE_FILES
Built under linux
Compiled at Jul 17 2003 20:17:04
%ENV:
PERL5LIB=":/data/gatekeeper/prod/cur_ver/lib/perl"
@INC:
/data/gatekeeper/prod/cur_ver/lib/perl
/data/gatekeeper/util/lib/perl5/5.8.0/i686-linux
/data/gatekeeper/util/lib/perl5/5.8.0
/data/gatekeeper/util/lib/perl5/site_perl/5.8.0/i686-linux
/data/gatekeeper/util/lib/perl5/site_perl/5.8.0
/data/gatekeeper/util/lib/perl5/site_perl

=======================================================================
Solaris configuration returning correct results.
=======================================================================
Summary of my perl5 (revision 5.0 version 8 subversion 0) configuration:
Platform:
osname=solaris, osvers=2.8, archname=sun4-solaris
uname='sunos solaris 5.8 generic_108528-11 sun4u sparc
sunw,ultra-5_10 '
config_args='-Dcc=gcc -B/usr/ccs/bin/'
hint=recommended, useposix=true, d_sigaction=define
usethreads=undef use5005threads=undef useithreads=undef
usemultiplicity=undef
useperlio=define d_sfio=undef uselargefiles=define usesocks=undef
use64bitint=undef use64bitall=undef uselongdouble=undef
usemymalloc=n, bincompat5005=undef
Compiler:
cc='gcc -B/usr/ccs/bin/', ccflags ='-fno-strict-aliasing
-D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64',
optimize='-O',
cppflags='-fno-strict-aliasing'
ccversion='', gccversion='3.1', gccosandvers='solaris2.8'
intsize=4, longsize=4, ptrsize=4, doublesize=8, byteorder=4321
d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=16
ivtype='long', ivsize=4, nvtype='double', nvsize=8, Off_t='off_t',
lseeksize=8
alignbytes=8, prototype=define
Linker and Libraries:
ld='gcc -B/usr/ccs/bin/', ldflags =' -L/usr/local/lib '
libpth=/usr/local/lib /usr/lib /usr/ccs/lib
libs=-lsocket -lnsl -lgdbm -ldl -lm -lc
perllibs=-lsocket -lnsl -ldl -lm -lc
libc=/lib/libc.so, so=so, useshrplib=false, libperl=libperl.a
gnulibc_version=''
Dynamic Linking:
dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags=' '
cccdlflags='-fPIC', lddlflags='-G -L/usr/local/lib'


Characteristics of this binary (from libperl):
Compile-time options: USE_LARGE_FILES
Built under solaris
Compiled at Jul 22 2002 02:55:19
%ENV:

PERL5LIB=":/oss/current/rc4498/work/projects/util/usr/local/lib/perl5/site_perl/5.8.0"
@INC:

/oss/current/rc4498/work/projects/util/usr/local/lib/perl5/site_perl/5.8.0/sun4-solaris

/oss/current/rc4498/work/projects/util/usr/local/lib/perl5/site_perl/5.8.0
/usr/local/lib/perl5/5.8.0/sun4-solaris
/usr/local/lib/perl5/5.8.0
/usr/local/lib/perl5/site_perl/5.8.0/sun4-solaris
/usr/local/lib/perl5/site_perl/5.8.0
/usr/local/lib/perl5/site_perl/5.6.1
/usr/local/lib/perl5/site_perl

=======================================================================
Cygwin on Windows Configuration returning correct results
=======================================================================
Summary of my perl5 (revision 5.0 version 8 subversion 0) configuration:
Platform:
osname=cygwin, osvers=1.3.22(0.7832), archname=cygwin-multi-64int
uname='cygwin_nt-5.0 ismene 1.3.22(0.7832) 2003-03-18 09:20 i586
unknown unknown cygwin '
config_args='-de -Dmksymlinks -Dusemultiplicity -Duse64bitint
-Doptimize=-O3 -Dman3ext=3pm'
hint=recommended, useposix=true, d_sigaction=define
usethreads=undef use5005threads=undef useithreads=undef
usemultiplicity=define
useperlio=define d_sfio=undef uselargefiles=define usesocks=undef
use64bitint=define use64bitall=undef uselongdouble=undef
usemymalloc=y, bincompat5005=undef
Compiler:
cc='gcc', ccflags ='-DPERL_USE_SAFE_PUTENV -fno-strict-aliasing',
optimize='-O3',
cppflags='-DPERL_USE_SAFE_PUTENV -fno-strict-aliasing'
ccversion='', gccversion='3.2 20020927 (prerelease)', gccosandvers=''
intsize=4, longsize=4, ptrsize=4, doublesize=8, byteorder=12345678
d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=12
ivtype='long long', ivsize=8, nvtype='double', nvsize=8,
Off_t='off_t', lseeksize=4
alignbytes=8, prototype=define
Linker and Libraries:
ld='ld2', ldflags =' -s -L/usr/local/lib'
libpth=/usr/local/lib /usr/lib /lib
libs=-lgdbm -ldb -lcrypt -lutil -lgdbm_compat
perllibs=-lcrypt -lutil -lgdbm_compat
libc=/usr/lib/libc.a, so=dll, useshrplib=true, libperl=libperl.a
gnulibc_version=''
Dynamic Linking:
dlsrc=dl_dlopen.xs, dlext=dll, d_dlsymun=undef, ccdlflags=' -s'
cccdlflags=' ', lddlflags=' -s -L/usr/local/lib'


Characteristics of this binary (from libperl):
Compile-time options: MULTIPLICITY USE_64_BIT_INT USE_LARGE_FILES
PERL_IMPLICIT_CONTEXT
Built under cygwin
Compiled at Aug 29 2003 12:06:59
%ENV:
CYGWIN="ntsec tty"
@INC:
/usr/lib/perl5/5.8.0/cygwin-multi-64int
/usr/lib/perl5/5.8.0
/usr/lib/perl5/site_perl/5.8.0/cygwin-multi-64int
/usr/lib/perl5/site_perl/5.8.0
/usr/lib/perl5/site_perl

 

[gnari]

I'm trying to do development on a Linux laptop to port to Solaris.
However, I've run into a pack command that's returning incorrect results
on my laptop.

I'm using Perl 5.8.0 on all platforms. I've included the output of perl
-V also below because the problem seems to be so low level.

Here's the command...

perl -e 'print pack("I", 149);'|od -x

and what does this do?:
perl -e 'print pack("I", 149);'|od -t x1


gnari

 

[Ralph]

One more observation on this - I physically copied all the perl
libraries and perl binary from the working Linux (Suse) system to the
laptop where the incorrect results where happening, and in spite of
working correctly on the other machine, they returned the incorrect
results on the laptop. That means it has nothing to do with Perl per
se - it's actually a problem at the system level. Hmmm. I'd sure
like to get to the bottom of this.

Anyway thanks for reading this.

Ralph

 

[Ralph]

One more thing - I did an ldd on the Perl binaries on the good and bad
systems, and got this...

Good System
=======================================================
libnsl.so.1 => /lib/libnsl.so.1 (0x40023000)
libdl.so.2 => /lib/libdl.so.2 (0x40038000)
libm.so.6 => /lib/libm.so.6 (0x4003b000)
libpthread.so.0 => /lib/libpthread.so.0 (0x4005e000)
libc.so.6 => /lib/libc.so.6 (0x40073000)
libcrypt.so.1 => /lib/libcrypt.so.1 (0x40191000)
libutil.so.1 => /lib/libutil.so.1 (0x401c3000)
/lib/ld-linux.so.2 => /lib/ld-linux.so.2 (0x40000000)

Bad System
=======================================================
libperl.so =>
/usr/lib/perl5/5.8.0/i386-linux-thread-multi/CORE/libperl.so
(0x40017000)
libnsl.so.1 => /lib/libnsl.so.1 (0x40152000)
libdl.so.2 => /lib/libdl.so.2 (0x40167000)
libm.so.6 => /lib/tls/libm.so.6 (0x4016a000)
libpthread.so.0 => /lib/tls/libpthread.so.0 (0x4018c000)
libc.so.6 => /lib/tls/libc.so.6 (0x42000000)
libcrypt.so.1 => /lib/libcrypt.so.1 (0x4019a000)
libutil.so.1 => /lib/libutil.so.1 (0x401c7000)
/lib/ld-linux.so.2 => /lib/ld-linux.so.2 (0x40000000)

A major difference is the bad system is using libperl.so, but I think
I eliminated that when I copied the good Perl to the bad (laptop)
system and the problem persisted.

The only other difference I can see is that the bad (laptop) system is
using math, thread and C libraries under a "tls" directory. I know
TLS as the next version of SSL. Is this what this means? I tls a set
of redhat specific libraries? Or?

One good thing about something like this - it forces me to poke around
and I inevitably learn something. Still I'd like to solve the
problem.

Thanks again. Sorry for all the follow-up posts.

Ralph

 

[Ralph]

and what does this do?:
perl -e 'print pack("I", 149);'|od -t x1


gnari

Actually it's perl -e 'print pack("I", 149)' | od -x

Try these...

perldoc -f pack
man od

In a nutshell pack creates a binary in-memory representation of the
decimal number 149 and prints it out to the screen. Since it's
binary, it's not meant to be interpretted by human eyes. So I pipe it
through od (octal dump) with a -x switch so it prints it out to the
screen as hexidecimal data so I can see what's actually there.

Ralph