The following are brief descriptions of the Intuition functions that
relate to the use of input and output under Intuition. See the Amiga ROM
Kernel Reference Manual: Includes and Autodocs for details on each
function call.

          Table 9-1: Functions for Intuition Input and Output
  ____________________________________________________________________
 |                                                                    |
 |    Function                    Description                         |
 |====================================================================|
 |  modifyidcmp()  change the message filter for an idcmp.            |
 |                 Starting in V37, this function has a return value. |
 |____________________________________________________________________|