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AutoLoader.pm
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1997-03-29
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package AutoLoader;
use Carp;
=head1 NAME
AutoLoader - load functions only on demand
=head1 SYNOPSIS
package FOOBAR;
use Exporter;
use AutoLoader;
@ISA = (Exporter, AutoLoader);
=head1 DESCRIPTION
This module tells its users that functions in the FOOBAR package are to be
autoloaded from F<auto/$AUTOLOAD.al>. See L<perlsub/"Autoloading">.
=cut
AUTOLOAD {
my $name = "auto/$AUTOLOAD.al";
$name =~ s#::#/#g;
eval {require $name};
if ($@) {
# The load might just have failed because the filename was too
# long for some old SVR3 systems which treat long names as errors.
# If we can succesfully truncate a long name then it's worth a go.
# There is a slight risk that we could pick up the wrong file here
# but autosplit should have warned about that when splitting.
if ($name =~ s/(\w{12,})\.al$/substr($1,0,11).".al"/e){
eval {require $name};
}
elsif ($AUTOLOAD =~ /::DESTROY$/) {
eval "sub $AUTOLOAD {}";
}
if ($@){
$@ =~ s/ at .*\n//;
croak $@;
}
}
goto &$AUTOLOAD;
}
sub import {
my ($callclass, $callfile, $callline,$path,$callpack) = caller(0);
($callpack = $callclass) =~ s#::#/#;
# Try to find the autosplit index file. Eg., if the call package
# is POSIX, then $INC{POSIX.pm} is something like
# '/usr/local/lib/perl5/POSIX.pm', and the autosplit index file is in
# '/usr/local/lib/perl5/auto/POSIX/autosplit.ix', so we require that.
#
# However, if @INC is a relative path, this might not work. If,
# for example, @INC = ('lib'), then
# $INC{POSIX.pm} is 'lib/POSIX.pm', and we want to require
# 'auto/POSIX/autosplit.ix' (without the leading 'lib').
#
if (defined($path = $INC{$callpack . '.pm'})) {
# Try absolute path name.
$path =~ s#^(.*)$callpack\.pm$#$1auto/$callpack/autosplit.ix#;
eval { require $path; };
# If that failed, try relative path with normal @INC searching.
if ($@) {
$path ="auto/$callpack/autosplit.ix";
eval { require $path; };
}
carp $@ if ($@);
}
}
1;