Dear Monks,

I have the following script which I ran on 2 different machines: 

#!/usr/local/bin/perl
#
 use strict;
 use warnings;
 use Config;

 print "Byte order:   $Config{byteorder}\n";    # expect byteorder='43
+21' or '1234';

 my $hexstring = "01020304";        # Hex number
 my $decnumber = hex $hexstring;

 print "Hex: $hexstring  is  Dec:  $decnumber\n";        # expect 1690
+9060

 my $netnumber = pack( "N", $decnumber );

 print "Dec: $decnumber  is  'N': '",unpack("H8",$netnumber),"'  as Ne
+twork or Big-endian\n";

 my $Nonnetnumber = pack( "V", $decnumber );         # Vax or little-e
+ndian

 print "Dec: $decnumber  is  'V': '",unpack("H8",$Nonnetnumber),"'  as
+ Vax or Little-endian\n";

 $Nonnetnumber = pack( "L", $decnumber );         # as native format

 print "Dec: $decnumber  is  'L': '",unpack("H8",$Nonnetnumber),"'  as
+ native format\n";

[download]
The results were: 
On Aix 5.2 on RS/6000 ( powerpc-ibm-aix5.2.0.0 )

# pyrperl ./pack.pl         
Byte order:   4321
Hex: 01020304  is  Dec:  16909060
Dec: 16909060  is  'N': '01020304'  as Network or Big-endian
Dec: 16909060  is  'V': '04030201'  as Vax or Little-endian
Dec: 16909060  is  'L': '01020304'  as native format

On Debian Linux on 64bit AMD ( Debian 4.4.5-8 )

# pyrperl ./pack.pl
Byte order:   1234
Hex: 01020304  is  Dec:  16909060
Dec: 16909060  is  'N': '01020304'  as Network or Big-endian
Dec: 16909060  is  'V': '04030201'  as Vax or Little-endian
Dec: 16909060  is  'L': '04030201'  as native format

[download]
The results agree with Writing endian-independent code in C. My knowledge of big-endian came from writing machine to machine transfer software for IBM in the '70s.

The background was that IBM 32-bit mainframes were big-endian and expensive, and the new in-expensive (???) 8-bit boxes were little-endian.

As you can see the 'N' and 'V' 'pack' formats are the same on both architectures but the native formats are different. Perl's 'pack' is correct, but the documentation examples are incorrect.

Regards...Ed

"Well done is better than well said." - Benjamin Franklin

In reply to Re: Is the documentation for Perl 5.20 'pack' correct? by flexvault
in thread Is the documentation for Perl 5.20 'pack' correct? by flexvault

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