sub AUTOLOAD {
    # This AUTOLOAD is used to 'autoload' constants from the constant()
    # XS function.  If a constant is not found then control is passed
    # to the AUTOLOAD in AutoLoader.

    my($constname);
    ($constname = $AUTOLOAD) =~ s/.*:://;
    #reset $! to zero to reset any current errors.
    local $! = 0;
    $val = constant($constname, @_ ? $_[0] : 0);

    if ($! != 0) {
    if ($! =~ /Invalid/) {
        $AutoLoader::AUTOLOAD = $AUTOLOAD;
        goto &AutoLoader::AUTOLOAD;
    }
    else {

            # Added by JOC 06-APR-96
            # $pack = 0;
        $pack = 0;
        ($pack,$file,$line) = caller;
            print "Your vendor has not defined Win32::Pipe macro $constname, used in $file at line $line.";
    }
    }
    eval "sub $AUTOLOAD { $val }";
    goto &$AUTOLOAD;
}