Function SecTransformCopyExternalRepresentation 

pub unsafe extern "C-unwind" fn SecTransformCopyExternalRepresentation(
    transform_ref: &SecTransform,
) -> CFRetained<CFDictionary>

👎Deprecated: SecTransform is no longer supported

Available on crate feature SecTransform only.

Create a CFDictionaryRef that contains enough information to be able to recreate a transform.

Parameter transformRef: The transformRef to be externalized.

This function returns a CFDictionaryRef that contains sufficient information to be able to recreate this transform. You can pass this CFDictionaryRef to SecTransformCreateFromExternalRepresentation to be able to recreate the transform. The dictionary can also be written out to disk using the techniques described here.

http://developer.apple.com/mac/library/documentation/CoreFoundation/Conceptual/CFPropertyLists/Articles/Saving.html

Safety

transform_ref should be of the correct type.