Building Blockchain Projects

Callback functions

Once your result is ready, Oraclize will send a transaction back to your contract address and invoke one of these three methods:

• either __callback(bytes32 myid, string result). Myid is a unique ID for every query. This ID is returned by the oraclize_query method. If you have multiple oraclize_query calls in your contract, then this is used to match the query this result is for.
• If you requested for the TLS Notary proof, this is the result: __callback(bytes32 myid, string result, bytes proof)
• As a last resort, if the other methods are absent, the fallback function is function()

Here is an example of the __callback function:

function __callback(bytes32 myid, string result) {  if (msg.sender != oraclize_cbAddress()) throw; ...