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Inside Macintosh: Interapplication Communication /

Chapter 6 - Resolving and Creating Object Specifier Records / Reference to Resolving and Creating Object Specifier Records

Routines for Resolving and Creating Object Specifier Records / Creating Object Specifier Records

CreateCompDescriptor

You can use the CreateCompDescriptor function to create a comparison descriptor record.

FUNCTION CreateCompDescriptor (comparisonOperator: DescType;
                               VAR operand1: AEDesc; 
                               VAR operand2: AEDesc; 
                               disposeInputs: Boolean; 
                               VAR theDescriptor: AEDesc)
                               : OSErr;

comparisonOperator

The comparison operator for comparing the descriptor records in the operand1 and operand2 parameters. The operator is specified by the constants listed in the description that follows.

operand1

An object specifier record.

operand2

A descriptor record (which can be an object specifier record or any other descriptor record) whose value is to be compared to the value of operand1.

disposeInputs

A Boolean value indicating whether the function (TRUE) or your application (FALSE) should dispose of the descriptor records for the two operands.

theDescriptor

The comparison descriptor record created by CreateCompDescriptor.

DESCRIPTION

The CreateCompDescriptor function creates a comparison descriptor record, which specifies how to compare one or more Apple event objects with either another Apple event object or a descriptor record.

The actual comparison of the two operands is performed by the object-comparison function provided by the client application. The way a comparison operator is interpreted is up to each application.

These are the currently defined standard comparison operators:

Constant	Meaning
kAEGreaterThan	The value of operand1 is greater than the value of operand2.
kAEGreaterThanEquals	The value of operand1 is greater than or equal to the value of operand2.
kAEEquals	The value of operand1 is equal to the value of operand2.
kAELessThan	The value of operand1 is less than the value of operand2.
kAELessThanEquals	The value of operand1 is less than or equal to the value of operand2.
kAEBeginsWith	The value of operand1 begins with the value of operand2 (for example, the string "operand" begins with the string "opera").
kAEEndsWith	The value of operand1 ends with the value of operand2 (for example, the string "operand" ends with the string "and").
kAEContains	The value of operand1 contains the value of operand2 (for example, the string "operand" contains the string "era").

RESULT CODES

noErr	0	No error occurred
paramErr	-50	Error in parameter list
memFullErr	-108	Not enough room in heap zone
errAECoercionFail	-1700	Data could not be coerced to the requested Apple event data type
errAEWrongDataType	-1703	Wrong Apple event data type
errAENotAEDesc	-1704	Not a valid descriptor record
errAEBadListItem	-1705	Operation involving a list item failed

SEE ALSO

For an example of how to use the CreateCompDescriptor function to create a comparison descriptor record, see "Specifying a Test," which begins on page 6-75.