As long as the neither CRT or MICE is excluded using a conditional define, the mouse macros are safe to use even when a mouse is not present.
When a program starts up, the mouse will be initialized automatically. However, it will not be made visible by default. A call to MouseShow will be required to make the mouse cursor visible.
Also, the mouse will be made invisible when changing video modes.
WARNING: All macros that are part of CRT require DS to be the program Data Segment. For flat binary (COM files), this means DS must equal CS when using these macros.
General mouse functions:
| MouseShow | Make the mouse cursor visible. |
| MouseHide | Make the mouse cursor invisible. |
| MouseVisible | Test if mouse cursor is visible. |
| MouseInvisible | Test if mouse cursor is not visible. |
| MouseEvent | Test if a mouse event is waiting. |
| MouseOverflow | Test if the mouse events have been discarded. |
| MouseRead | Fetch next mouse event and remove it from the buffer. |
| MousePreview | Fetch next mouse event but leave it in the buffer. |
Mouse functions which are generally for internal usage and handled automatically:
| MouseAvailable | Test if mouse is present and initialized. |
| MouseUnavailable | Test if mouse is not resent or not initialized. |