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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 / Coercing Descriptor Types

AECoercePtr

You can use the AECoercePtr function to coerce data to a desired descriptor type. If successful, it creates a descriptor record containing the newly coerced data.

FUNCTION AECoercePtr (typeCode: DescType; dataPtr: Ptr; 
                      dataSize: Size; toType: DescType; 
                      VAR result: AEDesc): OSErr;

typeCode

The descriptor type of the source data.

dataPtr

A pointer to the data to be coerced.

dataSize

The length, in bytes, of the data to be coerced.

toType

The desired descriptor type of the resulting descriptor record.

result

The resulting descriptor record.

DESCRIPTION

The AECoercePtr function creates a new descriptor record by coercing the specified data to a descriptor record of the specified descriptor type. You should use the AEDisposeDesc function to dispose of the resulting descriptor record once you are finished using it.

If AECoercePtr returns a nonzero result code, it returns a null descriptor record unless the Apple Event Manager is not available because of limited memory.

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

SEE ALSO

For a description of the AEDisposeDesc function, see page 4-93.