Can one element (in path 1) pass some parameters to another element (in path2)?

[chuanic]

PATH1: FromDevice -> Element1 -> ToDevice;
PATH2: FromDevice -> Element2 -> ToDevice;

Can element1 pass an parameter to element2??

[pallas]

Element2 can take a pointer to Element1 and extract the value itself.

[bcronje]

To add an example of what @pallas is saying, one way to get this pointer:

    int MyElement::configure(Vector<String> &conf, ErrorHandler *errh)
    {
        String ename;

        if (Args(conf, this, errh)
                .read_m("ELEMENT", ename)
                .complete() < 0)
            return -1;

        MyOtherElement *myelem;
        if (Element* e = router()->find(ename, this)) {
            if (!(myelem = dynamic_cast<MyOtherElement *>(e))) {
                return errh->error("%s is not a MyOtherElement element", ename.c_str());
            }
        } else {
            return errh->error("%s does not name an element", ename.c_str());

        // Here myelem is a valid pointer to the MyOtherElement instance.

        return 0;
    }

And then in your click config file have something like:

FromDevice(eth0) -> myotherelement::MyOtherElement -> Discard;
FromDevice(eth1) -> myelement::MyElement(ELEMENT myotherelement) -> Discard;

[chuanic]

First, i really appreciate your guys.

@bcronje Your way is take parameters from myotherelement. I want to pass parameters from myotherelement to myelement.

Maybe i should explain more particularly.
our purpose: MyOtherElement configure some parameters such as spi and rpl, and now MyElement can directly use these two parameters without include MyOtherElement or even more modify this mudole.

[chuanic]

Thanks for your answering.

Now i have done this: myotherelement can pass myelement parameters (myotherelement not take parameters from myotherelement)

The part of source code is as below:

------------------------this is config-----------------------

------------------------this is MyOtherElement-----------------------

------------------------this is MyElement-----------------------