There are several ways to do that, as always... one elegant way of doing that is using the AutoLoader (as e.g. POSIX does it) together with Exporter. To use that, you have to make up a package file (say, General.pm)

package General;
use AutoLoader qw(AUTOLOAD);
use Exporter;
# functions your main script might want to import
our @EXPORT_OK = qw(
    func1 func2 ...
);
1;
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and wrap the content of each file into a subroutine:

original:

#!/usr/bin/perl
# file prog1.pl

# main program
my ($arg_a, $arg_b) = @ARGV;

; # ... more perl code

# end main
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wrapped:

#!/usr/bin/perl
# file func1.al

package General; # the function must be compiled into its package.

sub func1 {
    # main program
    my ($arg_a, $arg_b) = @_;

    ; # ... more perl code

    # end main
}
unless (caller) {
    func1(@ARGV);
}
1; # <-- important!
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The package file General.pm lives anywhere where perl can find it. Make a directory ./auto/General/ in the directory where General.pm lives and stuff the wrapped function files (*.al files) there. Write the file ./auto/General/autosplit.ix

package General; 
# optionally put your subs here to predeclare them at package loading
sub func1 ;
1; # last line, important
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That's it. Now you can use General.pm in your main script

#!/usr/bin/perl

use General qw(func1 otherfunc); # functions from General you want to 
+call directly

my $result = func1($arg_a, $arg_b);
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and each function file will be compiled on demand, that is, only if you actually are calling its function.

_($_=" "x(1<<5)."?\n".q·/)Oo.  G°\        /
                              /\_¯/(q    /
----------------------------  \__(m.====·.(_("always off the crowd"))."·
");sub _{s./.($e="'Itrs `mnsgdq Gdbj O`qkdq")=~y/"-y/#-z/;$e.e && print}