Reply Messages

The following three messages are sent as replies to other messages.

B_MESSAGE_NOT_UNDERSTOOD

This message doesn't contain any data. The system sends it as a reply to a message that the receiving thread's chain of BHandlers does not recognize. See MessageReceived() and ResolveSpecifier() in the BHandler class of the Application Kit.

B_NO_REPLY

This message doesn't contain any data. It's sent as a default reply to another message when the original message is about to be deleted. The default reply is sent only if a synchronous reply is expected and none has been sent. See the SendReply() function in the BMessage class of the Application Kit.

B_REPLY

This constant identifies a message as being a reply to a previous message. The data in the reply depends on the circumstances and, particularly, on the original message. For replies to scripting messages, it generally has a "result" field with requested data and an "error" field with an error code reporting the success or failure of the scripted request.