From perldoc -f use:

  [use] is exactly equivalent to

    BEGIN { require Module; import Module LIST; }

  except that Module must be a bareword.

So if you have Bar.pm:

package Bar;
sub import {
   warn "Arguments are: @_";
}
1;
[download]

When you use Bar, you get:

% perl -e 'use Bar qw/abc def/'
Arguments are: Bar abc def at Bar.pm line 6.