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Inside Macintosh: QuickDraw GX Environment and Utilities /
Chapter 6 - Message Manager / Message Manager Reference
Functions / Sending and Forwarding Messages


You can use the ForwardMessage function to specify the message to be forwarded to the next message handler.

OSErr ForwardMessage (long messageSelector,...);
The number of the message to be forwarded.
additional parameters
Parameters associated with the message sent.
function result
An error of type OSErr.
The ForwardMessage function forwards the message specified by the messageSelector parameter to the next message handler. This function is like the ForwardThisMessage function, except that any message may be forwarded. The messageSelector parameter indicates which message is to be forwarded, as in the SendMessage function. By definition, all messages return a function result of type OSErr.

The ellipsis character at the end of the parameter list indicates that the remaining additional parameters are unspecified; the caller must pass whatever parameters are expected by the recipient of the message identified by the messageSelector parameter. By definition, all message overrides return a result of type OSErr. It is an error to call the ForwardMessage function except from within a message handler. In any other case, behavior is undefined.

The OSErr error returned may indicate that the message could not be forwarded. If no error occurs, the function result is noErr. In addition, the receiving message handler may return an error of type OSErr.

To send a specified message to the current message target, use the SendMessage function described in the previous section.

To forward the current message to the next message handler, use the ForwardThisMessage function described in the next section.

The use of the ForwardMessage function is described in the section "Sending and Forwarding Messages" beginning on page 6-15.

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© Apple Computer, Inc.
7 JUL 1996