Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!rutgers!apple!Apple.COM!lsr
From: lsr@Apple.COM (Larry Rosenstein)
Newsgroups: comp.sys.mac.programmer
Subject: Re: Locking executable resources
Message-ID: <1632@internal.Apple.COM>
Date: 2 May 89 18:31:46 GMT
References: <4170@druco.ATT.COM>
Sender: usenet@Apple.COM
Distribution: comp
Organization: Objects-R-Us,  Apple Computer, Inc.
Lines: 22

In article <4170@druco.ATT.COM> jon@druco.ATT.COM (GotowJK) writes:
> The dilemma is that this occurs because _somebody else's_ INIT resource 
> is not locked, and I can't control that.  This seems to be major 
> problem - or am I missing something?  

An important rule in patching traps is that your patch code has to be at 
least as careful as the trap being patched with respect to allocating 
memory and saving registers.  If the trap you are patching does not 
allocate memory, then your patch can't either.  Your patch has to save at 
least the registers that the original patch saves.  (This is especially 
important when patching the Resource Manager, since it saves more than the 
usual set of registers.)

In your case, InitGraf doesn't allocate memory, but SysBeep does.  So 
technically, you are "in the wrong."  (On the other hand, those INIT 
should be locking themselves down.)

Larry Rosenstein, Apple Computer, Inc.
Object Specialist

Internet: lsr@Apple.com   UUCP: {nsc, sun}!apple!lsr
AppleLink: Rosenstein1