Sets a static value for an attribute in a transform.


func SecTransformSetAttribute(_ transformRef: SecTransform, _ key: CFString, _ value: CFTypeRef, _ error: UnsafeMutablePointer<Unmanaged<CFError>?>?) -> Bool



The transform whose attribute is to be set.


The name of the attribute to be set. See Transform Attributes for a list of valid keys and possible values.


The static value to set for the named attribute.


A pointer that the function uses to provide an error object with details if an error occurs. The caller becomes responsible for the object's memory. Pass NULL to ignore the error.

Return Value

A Boolean set to true if the call succeeds. Otherwise, the error parameter contains information about the failure.


This function is useful for things like iteration counts and other non-changing values. It returns an error and the named attribute is not changed if SecTransformExecute(_:_:) has already been called on the transform.

Compare this function with the SecTransformConnectTransforms(_:_:_:_:_:_:) function which sets derived data.

See Also

Transform Characteristics

func SecTransformGetAttribute(SecTransform, CFString) -> CFTypeRef?

Gets the current value of a transform attribute.

Transform Attributes

Specify the attributes of a transform.

typealias SecTransformAttribute

A direct reference to a security transform attribute.

typealias SecTransformStringOrAttribute

A type that may be either a string or an attribute reference.

enum SecTransformMetaAttributeType

The keys that describe the metadata attributes of transform attributes.