Path: utzoo!attcan!uunet!seismo!sundc!pitstop!sun!amdcad!ames!pasteur!ucbvax!dewey.soe.berkeley.edu!oster
From: oster@dewey.soe.berkeley.edu (David Phillip Oster)
Newsgroups: comp.sys.mac.programmer
Subject: Re: 32K jump table limit
Keywords: MacApp
Message-ID: <25797@ucbvax.BERKELEY.EDU>
Date: 25 Aug 88 07:49:25 GMT
References: <3425@Portia.Stanford.EDU>
Sender: usenet@ucbvax.BERKELEY.EDU
Reply-To: oster@dewey.soe.berkeley.edu.UUCP (David Phillip Oster)
Organization: School of Education, UC-Berkeley
Lines: 40

The 4000 global procedure limit is a problem. There is a workaround in C
and a workaround in pascal.

In C, divide your program into modules, each module in its own files. All
those procedures that are called only from within that module (and for a
well written program, that should be most of the procedures, should be
declared "static" which keeps them visible only inside that file, and on
most compilers generated local jsrs that don't use the jump table. Of
course, if you pass out pointers to procedures, they will get jump table
entries whether you declare them static or not.

In Pascal, define helper procedures lexically inside other procedures:

procedure entry;
  procedure helper;
  begin { helper }
  ...
  end { helper } ;
begin { entry }
...
  helper;
  helper;
end {entry } ;

Beware, if you pass a pointer to such a procedure to the operating system,
it will not work.

Beyond that, and you have to go to executable code resources that take an
integer a function selector, like the PACKs do.

Yes, it is a pain, but it is a chance to improve the style and
maintainability of your code: It is easier to understand a program where
the original author has been careful to delimit the scope of the
procedures: If you know that procedure "x" is only called inside file "a",
then you don't have to waste time thinking about the implications if it
were called from file "b".

--- David Phillip Oster            --When you asked me to live in sin with you
Arpa: oster@dewey.soe.berkeley.edu --I didn't know you meant sloth.
Uucp: {uwvax,decvax,ihnp4}!ucbvax!oster%dewey.soe.berkeley.edu