www.delorie.com/djgpp/doc/rbinter/48.html   search  
2F4B01

Category: DOS-based task switchers/multitaskers
Flags: callout or callback (usually hooked rather than called)

INT 2F - DOS 5+ TASK SWITCHER - BUILD CALLOUT CHAIN

	AX = 4B01h
	CX:DX -> task switcher entry point (see #02819)
	ES:BX = 0000h:0000h
Return: ES:BX -> callback info structure (see #02817) or 0000h:0000h
Notes:	called by the task switcher
	this function is hooked by clients which require notification of task
	  switcher activities; the call must first be passed on to the prior
	  handler with registers unchanged using a simulated interrupt.	 On
	  return, the client must build a callback info structure and store
	  the returned ES:BX in the "next" field, then return the address of
	  its own callback info structure.
	a client program must add itself to the notification chain if it
	  provides services to other programs; before terminating, it must
	  remove itself from the chain by calling the task switcher's entry
	  point with AX=0005h (see #02819)
	the task switcher entry point should not be saved, as it is subject to
	  change and will be provided on any notification call
	the Windows 3.1 Standard Mode supports this API
SeeAlso: AX=160Bh,AX=4B02h


  webmaster   donations   bookstore     delorie software   privacy  
  Copyright 2000   by Ralf Brown     Updated Jul 2000