> For the complete documentation index, see [llms.txt](https://trillbit.gitbook.io/trillbit-sdk/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://trillbit.gitbook.io/trillbit-sdk/ios-support/trill-sdk-for-ios/methods-and-callbacks/trill-sdk-callbacks-and-delegates.md).

# Trill SDK Callbacks and delegates

```
(void) onError: (int) error_code: (NSString*) errror;
```

The callback is triggered in case of any error. The callback returns back error code with the error

message as string.

```
(void) onInfo: (int) info_code: (NSString*) info;
```

The callback is triggered in the case when SDK needs to pass any information to the main

application. The callback returns back info code with the info message as string,

```
(void) onSDKReady;
```

The callback is triggered once SDK is initlised and ready to be used for sending and receiving

purpose.

```
(void) onPlayingCompleted;
```

The callback is triggered once SDK has completed playing, If the playing method is called with

repeat count 3 the callback will be received 3 times for every play completed

```
(void) onSendingCompleted;
```

The callback is triggered once SDK has completed the sending process If the playing method is

called with repeat count 3 the callback will be received when playing is completed for the 3rd time.

```
(void) onDecoded:(NSString*) payload;
```

The callback is triggered when SDK has received the TrillTone. Use the callback to receive decoded data on the main application.