&err( "Too Few Characters in Company Login Name" )
    if  length($compname) < 6;

##</code><code>##

$errmsg = "Too Few Characters in Company Login Name";
&err($errmsg) if (length($compname) < 6);

##</code><code>##

sub err {
    my( $errmsg )= @_;
    # ...
}

##</code><code>##

$errmsg = "Too Few Characters in Company Login Name";
&err() if (length($compname) < 6);