AEGetParamDesc(_:_:_:_:)
Gets a copy of the descriptor for a keyword-specified Apple event parameter from an Apple event or an Apple event record.
Declaration
func AEGetParamDesc(_ theAppleEvent: UnsafePointer<AppleEvent>!, _ theAEKeyword: AEKeyword, _ desiredType: DescType, _ result: UnsafeMutablePointer<AEDesc>!) -> OSErrParameters
- theAppleEvent:
A pointer to the Apple event to get the parameter descriptor from.
- theAEKeyword:
A keyword that specifies the desired Apple event parameter. Some keyword constants are described in 1527206 Keyword_parameter_constants.
- desiredType:
The descriptor type for the desired Apple event parameter. For a list of AppleScript’s predefined descriptor types, see 1542788 Descriptor_type_constants.
If the requested Apple event parameter is not of the desired type, the Apple Event Manager attempts to coerce it to the desired type. However, if you pass a value of
typeWildCard, no coercion is performed, and the descriptor type of the returned descriptor is the same as the descriptor type of the Apple event parameter. - result:
A pointer to a descriptor. On successful return, a copy of the descriptor for the specified Apple event parameter, coerced, if necessary, to the descriptor type specified by the
desiredTypeparameter. On error, a null descriptor. If the function returns successfully, your application should call the 1444208 Aedisposedesc function to dispose of the resulting descriptor after it has finished using it.
Return Value
A result code. See Result Codes.
Discussion
You typically call AEGetParamDesc to get a descriptor for an Apple event parameter to pass on to another Apple Event Manager routine. To get Apple event parameter data for your application to use directly, call AEGetParamPtr(_:_:_:_:_:_:_:).
If the actual parameter you are getting with AEGetParamDesc is a record, you can only request it as a typeAERecord, typeAEList, or typeWildcard. For any other type, AEGetParamDesc will return errAECoercionFail.
Version-Notes
Thread safe starting in OS X v10.2.