Constant function creating event

Question

Basically is it possible for constant functions to emit events? Example bellow:

I have Sample Contract which has a getData() function which does not modify any state, emits an event and returns a string value.

contract Sample {

    event ExampleEvent(string data_description);

    function getData() public constant returns (string) {
        ExampleEvent("From Sample contract");
        return "Event sent";
    }
}

Then I try to call it through nodejs with web3.js using .call() (this does not emit event)

SampleContract(abi).at(address).getInfo.call({from:{account});

I only receive the "Event sent" string as a response, but no event has been created.

However if I call this function via a transaction .sendTransaction()(this emits event)

SampleContract(abi).at(address).getInfo.sendTransaction({from:{account});

This returns the transaction hash as expected (since I'm creating a transaction) but it also creates a new event.

I understand that constant functions cannot change a contract state however a new event is not really part of the contract storage/state (events/logs are stored in the transaction logs)?

What is the reason for this not to be working, am I missing something obvious?

Answer 1

Events are used in transactions only. When you execute a transaction function you can't get the return value because transactions are not immediately mined and included in the blockchain.

Events allow you to get notified when the transaction has been mined in order to get the return value.

It makes no sense trying to call an Event inside a call function, given that they will return a value "immediately".