Using the right mouse button with evnt_multi in Assembler
           =========================================================

    You will probably have noticed that very few applications for the Atari
    make much use of the  right  mouse  button.  The  reason given was that
    there was no simple way for a GEM  program  to do it. It turns out that
    there has been a legal  way  to  do  it  all  along - Atari finally got
    around to documenting it a couple of  years ago, but only to registered
    developers.

    The evnt_multi AES call can be  programmed to recognise either the left
    OR right button click by setting the  clicks parameter to 256+1 and the
    mask parameter to 3. For example using the HiSoft MACRO call :-

    evnt_multi     #flags,#clicks,#mask,#bstate,#m1flags,etc,etc

    In the 'flags' parameter, bit  1  should  be  set  so that mouse button
    events will be recognised as well as any other bits required.

    'clicks' should be set to 1  or  2  to  recognise  one or two clicks as
    normal and bit 8 also  set  to  detect  the  right  button event. It is
    recommended that the parameter is written  as  #256+1 or #256+2 so that
    it is obvious what conditions are being monitored.

    The 'mask' parameter should be set to  3 so that left and right buttons
    are recognised.

    The 'bstate' parameter should be  set  to  0  to recognise 'mouse down'
    events.

    The  remaining  parameters  are  set   as  normal  depending  on  which
    facilities are required.

    On return from  evnt_multi  the  program  should  examine the int_out+6
    store to determine which button was  actually pressed, i.e. left button
    = 1 and right button = 2.

    See C\EVNT_BUT\EVNT_BUT.TXT file on  this  disk for further information
    on the history of this function.