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NAME
- AddMemHandler
-
Add a low memory handler to exec (V39)
SYNOPSIS
AddMemHandler(memHandler)
VOID AddMemHandler(struct Interrupt *);
A1
FUNCTION
This function adds a low memory handler to the system. The handler is described in the Interrupt structure. Due to multitasking issues, the handler must be ready to run the moment this function call is made. (The handler may be called before the call returns)
NOTES
Adding a handler from within a handler will cause undefined actions. It is safe to add a handler to the list while within a handler but the newly added handler may or may not be called for the specific failure currently running.
EXAMPLE
struct Interrupt *myInt; /* Assume it is allocated */
myInt->is_Node.ln_Pri=50; /* Relatively early; before RAMLIB */
/* Please fill in the name field! */
myInt->is_Node.ln_Name="Example Handler";
myInt->is_Data=(APTR)mydata_pointer;
myInt->is_Code=myhandler_code;
AddMemHandler(myInt);
... /* and so on */
_myhandler_code:
;
; Start off assuming we did nothing
;
handler_nop:
myInt->is_Node.ln_Pri=50; /* Relatively early; before RAMLIB */
/* Please fill in the name field! */
myInt->is_Node.ln_Name="Example Handler";
myInt->is_Data=(APTR)mydata_pointer;
myInt->is_Code=myhandler_code;
AddMemHandler(myInt);
... /* and so on */
_myhandler_code:
; This is the handler code
; We are passed a pointer to struct MemHandlerData
; in a0, the value of is_Data in a1 and
; ExecBase in a6.
; We must not break forbid!!!
; We are passed a pointer to struct MemHandlerData
; in a0, the value of is_Data in a1 and
; ExecBase in a6.
; We must not break forbid!!!
; Start off assuming we did nothing
;
moveq.l #MEM_DID_NOTHING,d0
move.l memh_RequestFlags(a0),d1
btst.l #MEMB_CHIP,d1 ; Did the failure happen in CHIP
beq.s handler_nop ; If not, we have nothing to do
bsr DoMyMagic ; Do the magic...
; DoMyMagic frees whatever we can and returns d0 set...
move.l memh_RequestFlags(a0),d1
btst.l #MEMB_CHIP,d1 ; Did the failure happen in CHIP
beq.s handler_nop ; If not, we have nothing to do
bsr DoMyMagic ; Do the magic...
; DoMyMagic frees whatever we can and returns d0 set...
rts ; Return with d0 set...
INPUTS
- memHandler
-
A pointer to a completely filled in Interrupt structure The priority field determine the position of the handler with respect to other handlers in the system. The higher the priority, the earlier the handler is called. Positive priorities will have the handler called before any of the library expunge vectors are called. Negative priority handlers will be called after the library expunge routines are called. (Note: RAMLIB is a handler at priority 0)