import external package

Noame has asked for the wisdom of the Perl Monks concerning the following question:

Hi,
I’m running the following program:

#! /usr/local/bin/perl

BEGIN
{
    push ( @INC, "$ENV{HOME}/Filesys-DiskSpace-0.05/lib"); # Filesys::
+DiskSpace - Perl df
}

use strict;
use warnings;
require Filesys::DiskSpace;

# file system /home or /dev/sda5
my $dir = "/home";
 
# get data for /home fs
my ($fs_type, $fs_desc, $used, $avail, $fused, $favail) = Filesys::Dis
+kSpace::df $dir; 
# calculate free space in %
my $df_free = (($avail) / ($avail+$used)) * 100.0;
 
# display message
my $out = sprintf("Disk space on $dir == %0.2f\n",$df_free);
print $out;
[download]

And Failed with the following error:
Can't call method "Filesys::DiskSpace::df" without a package or object reference at ./try.pl line 27.
Please advice.
Thanks.

Comment on import external package Select or Download Code

Replies are listed 'Best First'.
Re: import external package by JavaFan (Canon) on Jan 22, 2009 at 19:40 UTC
You choosed to do the require at run time. Which means that at compile time, Perl considers: `Filesys::DiskSpace::df $dir;` [download] to be an indirect object reference. One solution is use 'use' instead of require. Another is use explicite parenthesis when calling Filesys::DiskSpace::df. And if you use "use lib", you don't need the BEGIN block, and don't have to push on @INC yourself.	[reply] [d/l]
Re: import external package by kyle (Abbot) on Jan 22, 2009 at 19:44 UTC
I'm guessing this will work if you add the parentheses on your `df` call. `my ($fs_type, $fs_desc, $used, $avail, $fused, $favail) = Filesys::Dis +kSpace::df( $dir );` [download] Perl seems to think you're trying to use an indirect method call (like "`new Data::Dumper`" instead of "`Data::Dumper->new`"). Since you modify @INC in a `BEGIN` block, I think you can just use Filesys::DiskSpace instead of using require. If you still want to use `require` for some reason, you'll have to separately import its `df` to use it without parens.	[reply] [d/l] [select]
Re: import external package by Anonymous Monk on Jan 23, 2009 at 13:19 UTC
B::Deparse is useful to help diagnose your code Read more... (1417 Bytes) as is splain for decoding errors Read more... (1078 Bytes)	[reply] [d/l] [select]