NAME
MakeClass -- Create and initialize a boopsi class. (V36)
SYNOPSIS
iclass = MakeClass( ClassID, SuperClassID, SuperClassPtr,
D0 A0 A1 A2
InstanceSize, Flags )
D0 D1
struct IClass *MakeClass( UBYTE *, UBYTE *, struct IClass *,
UWORD, ULONG );
FUNCTION
For class implementors only.
This function creates a new public or private boopsi class.
The superclass should be defined to be another boopsi class:
all classes are descendants of the class "rootclass".
Superclasses can be public or private. You provide a name/ID
for your class if it is to be a public class (but you must
have registered your class name and your attribute ID's with
Commodore before you do this!). For a public class, you would
also call AddClass() to make it available after you have
finished your initialization.
Returns pointer to an IClass data structure for your
class. You then initialize the Hook cl_Dispatcher for
your class methods code. You can also set up special data
shared by all objects in your class, and point cl_UserData at it.
The last step for public classes is to call AddClass().
You dispose of a class created by this function by calling
FreeClass().
INPUTS
ClassID = NULL for private classes, the name/ID string for public
classes
SuperClassID = name/ID of your new class's superclass. NULL if
superclass is a private class
SuperClassPtr = pointer to private superclass. Only used if
SuperClassID is NULL. You are required never to provide
a NULL superclass.
InstanceSize = the size of the instance data that your class's
objects will require, beyond that data defined for
your superclass's objects.
Flags = for future enhancement, including possible additional
parameters. Provide zero for now.
RESULT
Pointer to the resulting class, or NULL if not possible:
- no memory for class data structure
- public superclass not found
- public class of same name/ID as this one already exists
NOTES
EXAMPLE
Creating a private subclass of a public class:
/* per-object instance data defined by my class */
struct MyInstanceData {
ULONG mid_SomeData;
};
/* some useful table I'll share use for all objects */
UWORD myTable[] = {
5, 4, 3, 2, 1, 0
};
struct IClass *
initMyClass()
{
ULONG __saveds myDispatcher();
ULONG hookEntry(); /* asm-to-C interface glue */
struct IClass *cl;
struct IClass *MakeClass();
if ( cl = MakeClass( NULL,
SUPERCLASSID, NULL, /* superclass is public */
sizeof (struct MyInstanceData),
0 ))
{
/* initialize the cl_Dispatcher Hook */
cl->cl_Dispatcher.h_Entry = hookEntry;
cl->cl_Dispatcher.h_SubEntry = myDispatcher;
cl->cl_Dispatcher.h_Data = (VOID *) 0xFACE; /* unused */
cl-cl_UserData = (ULONG) myTable;
}
return ( cl );
}
BUGS
The typedef 'Class' isn't consistently used. Class pointers
used blindly should be APTR, or struct IClass for class implementors.
SEE ALSO
FreeClass(), AddClass(), RemoveClass(), NewObject(),
Document "Basic Object-Oriented Programming System for Intuition"
and the "boopsi Class Reference" document.