Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!know!zaphod.mps.ohio-state.edu!usc!snorkelwacker!mit-eddie!bbn.com!apple!apple.com!chewy From: chewy@apple.com (Paul Snively) Newsgroups: comp.sys.mac.programmer Subject: Re: Inter-Process Communication Message-ID: <9615@goofy.Apple.COM> Date: 7 Aug 90 22:16:40 GMT Sender: usenet@Apple.COM Organization: Apple Computer, Inc. Lines: 58 References:<2286@polari.UUCP> <9596@goofy.Apple.COM> <4KPN20@cs.swarthmore.edu> In article <4KPN20@cs.swarthmore.edu> jackiw@cs.swarthmore.edu (Nick Jackiw) writes: > Protocol means code (in the non-programmer's sense of the word). > Any set of routines is governed by a protocol. Determining whether > data have changed, registering and querying about existing data types, > and other features of your driver may be unnecessary in a given IPC > situation. They are all necessary in the *general* IPC scenario, as I > stated. I see. My definition of "protocol" is "some means of communicating that is independent of the transport." The only "protocol" (by this definition) that Frank and I did was our simplistic versioning stuff. However, your point is well taken. > > This I'll agree with, and I'll even go so far as to ask what other kind of > > IPC makes sense on the Macintosh? > > Are you serious? Any cdev which communicates with an active INIT is doing > IPC, usually by accessing common storage in the system heap. Any program > which launches another program with a customized AppFile record is doing > IPC. (Remember MDS's integrated-but-separate editor, linker, and compiler?) > If your requirements aren't too serious, you could even do IPC by means > of the global deskscrap. All true, but cdev/INIT communication by heap-searching is a dangerous hack. The AppParmHandle example isn't a generalized IPC scheme, and the global deskscrap is _supposed_ to be "owned" by the user, with no software providing any surprises. What I meant by "makes sense" was a combination of architectural cleanliness combined with practicality. > > > Neither of these schemes has System 7-IPC's advantage of having a nicely > > > developed protocol for IPC between applications of which only one is > > > currently running. > > > > Unfortunately, neither does System 7.0's IAC suite; "store and forward" > > messages didn't make it in. [sigh] > > Ouch. I'll say. __________________________________________________________________________ Paul Snively Macintosh Developer Technical Support Apple Computer, Inc. chewy@apple.com Just because I work for Apple Computer, Inc. doesn't mean that I believe what they believe, or vice-versa. __________________________________________________________________________