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Inside Macintosh: Interapplication Communication /

Chapter 4 - Responding to Apple Events / Reference to Responding to Apple Events

Routines for Responding to Apple Events / Getting Data and Keyword-Specified Descriptor Records Out of AE Records

AEGetKeyDesc

You can use the AEGetKeyDesc function to get the descriptor record for a keyword-specified descriptor record. You can use this function to get a descriptor record out of an AE record or an Apple event record.

FUNCTION AEGetKeyDesc (theAERecord: AERecord; 
                       theAEKeyword: AEKeyword; 
                       desiredType: DescType; 
                       VAR result: AEDesc): OSErr;

theAERecord

The AE record containing the desired descriptor record.

theAEKeyword

The keyword that specifies the desired descriptor record.

desiredType

The desired descriptor type for the descriptor record to be returned; if the requested descriptor record is not of this type, the Apple Event Manager attempts to coerce it to this type. If the value of desiredType is typeWildCard, no coercion is performed, and the descriptor type of the returned descriptor record is the same as the descriptor type of the original descriptor record.

result

A copy of the keyword-specified descriptor record, coerced to the descriptor type specified in the desiredType parameter.

DESCRIPTION

The AEGetKeyDesc function returns a copy of the descriptor record for a keyword-specified descriptor record. Your application should call the AEDisposeDesc function to dispose of the resulting descriptor record after your application has finished using it.

If AEGetKeyDesc returns a nonzero result code, it returns a descriptor record of descriptor type typeNull. A descriptor record of this type does not contain any data.

RESULT CODES

noErr	0	No error
memFullErr	-108	Not enough room in heap zone
errAECoercionFail	-1700	Data could not be coerced to the requested descriptor type
errAEDescNotFound	-1701	Descriptor record was not found
errAENotAEDesc	-1704	Not a valid descriptor record
errAEReplyNotArrived	-1718	Reply has not yet arrived