Auxiliary Controls
controls and keep them transparent to applications that don't use color.
Central to a color control is the auxiliary control record (AuxCtlRec), which carries the control's color specifications; and the 'cctb' resource where all of
the auxiliary control's color table information is stored.
You can create a color control without creating an auxiliary control record
since a default color table with a standard set of control colors is loaded when
an application calls InitWindows. However, if you're using A/UX or if your application uses controls with different colors than those in the default,
Each customized control and every control (standard or otherwise) in an
A/UX system has to have its own AuxCtlRec but the ones that use the same colors can share the same color table. The control records themselves reside
in the application heap and hold all the information your application needs
when creating color controls.
In turn, the heart of the auxiliary control record is a handle to the control's
private color table. The rest of the record deals with administrative
information such as the record's place in relation to other, similar, auxiliary
control records. Multiple auxiliary control records exist in a linked list of
Handles. The low memory global AuxCtlHead is an AuxCtlPtr to the head of the
list. The list terminates with the default AuxCtlRec whose acNext and acOwner fields are NULL and CCTabHandle is the default color table.