Base Class DirectIO Method

2/27/2008

The DirectIO method and the DirectIOEvent event are used to provide functionality to the application that is not otherwise supported by the standard UPOS specification for a particular device type.

If a device has features that are not supported by the standard UPOS specification, a Service Object may implement a DirectIO method to give the application access to those features.

An example might be a LineDisplay device that supports multicolor output. Few, if any, LineDisplay-type devices support color output, but an independent hardware vendor (IHV) might produce such a device and want to have the new features available to applications.

Use of this method will make the application nonportable, since the implementation of the DirectIO method is vendor-specific. An application that uses a DirectIO method on Vendor A's LineDisplay device cannot depend on using a Vendor B's device.

DirectIOEvent

This event can be used to send vendor-specific information directly to the application. This event provides a means for a vendor-specific UPOS service to provide events to the application that are not otherwise supported by the UPOS control.

Using this event will make an application incompatible with devices from other vendors.

Show: