Identity Methods
Identity methods are used to identify an object, by providing the value of each of the arguments passed to the Create method to create that object. An identity method exists for each Create method argument, and typically is named by that argument.
Identity methods generally have a second output argument that is a pointer to the Create method argument to be returned; the return value of the method will indicate success or failure (as usual). However, identity methods that return an object handle do so directly rather than using an output argument.
| Example |
The mpiAxisCreate(...) method takes 2 arguments; an MPIControl handle and an axis number. Therefore, the Axis module declares 2 identity methods: mpiAxisControl(...) and mpiAxisNumber(...).
The mpiAxisControl(...) method returns the MPIControl handle with which the axis object was created. The mpiAxisNumber(...) method returns a value that indicates success or failure; if the value indicates success, the second argument points to a location that will be set to the axis number. |
|
