NAME

HookEntry: Assembler to HLL conversion stub for hook entry.

SYNOPSIS

result = HookEntry(hook, object, msg)
D0 A0 A2 A1

result = HookEntry(struct Hook *, Object *, APTR)

FUNCTION

By definition, a standard hook entry-point must receive the hook in A0, the object in A2, and the message in A1. If your hook entry-point is written in a high-level language and is expecting its parameters on the stack, then HookEntry() will put the three parameters on the stack and invoke the function stored in the hook h_SubEntry field.

This function is only useful to hook implementers, and is never called from C.

INPUTS

hook: Pointer to hook being invoked
object: Pointer to hook-specific data
msg: Pointer to hook-specific message

RESULT

result: aA hook-specific result.

NOTES

This function first appeared in the V37 release of amiga.lib. However, it does not depend on any particular version of the OS, and works fine even in V34.

This function does not preserve the contents of register A4, which is the responsibility of the hook function being called. If your code depends upon the contents of register A4 to remain unchanged you may need to use your own HookEntry implementation instead of the amiga.lib version.

EXAMPLE

If your hook dispatcher is this:

dispatch( struct Hook *hookPtr, Object *obj, APTR msg )
{

...

}

Then when you initialize your hook, you would say:

myhook.h_Entry = HookEntry; /* amiga.lib stub */
myhook.h_SubEntry = dispatch; /* HLL entry */