Choosing the TWAIN Loop Model

Your application can choose between allowing DTWAIN to start an internal TWAIN loop when acquiring images, or allow your application to adjust the main application loop.  TWAIN requires that a message loop must be started when a Source is enabled so that the messages that TWAIN sends are processed successfully.

If your programming language or environment cannot adjust the main application loop, you must choose Modal Acquisition processing (this is the default).  If you have access to the main application loop (languages such as C or C++), you should consider allowing your application to process the TWAIN messages.  Allowing your application to process the TWAIN messages is called Modeless Acquisition Processing.

Remember, the default is always Modal acquisition. To choose Modeless (or Modal processing, call DTWAIN_SetTwainMode.).  If you wish to use Modeless processing, here is a simple implementation of adjusting the main application loop

For a complete description of TWAIN processing see Introduction to DTWAIN Acquisition Processing.