Path: utzoo!attcan!uunet!decwrl!shelby!neon!pescadero.Stanford.EDU!philip
From: philip@pescadero.Stanford.EDU (Philip Machanick)
Newsgroups: comp.lang.c++
Subject: Re: porting C++ to tranputers
Keywords: ports, transputers
Message-ID: <1990Oct8.165450.1764@Neon.Stanford.EDU>
Date: 8 Oct 90 16:54:50 GMT
References: <1011@oscsunb.osc.edu> <59874@bbn.BBN.COM>
Sender: news@Neon.Stanford.EDU (USENET News System)
Reply-To: philip@pescadero.stanford.edu
Organization: Computer Science Department, Stanford University
Lines: 38

In article <59874@bbn.BBN.COM>, saustin@bbn.com (Steve Austin) writes:
[...]
|> I haven't ported AT&T's translator to RUN on a transputer, but it is
|> trivially easy to get C++ code compiled FOR a transputer - or anything
|> else really - if you have a C compiler for the target machine.
|> 
|> The program 'CC' is just a shell script which takes the C++ program,
|> runs it through the pre-processor, runs the output of this through
|> cfront and then compiles the resulting C code with the standard compiler.
|> 
|> It is easy to divert the last step (compiling with the default cc) and
|> then compile with the cross-compiler. If you don't want to mess around with
|> the shell script environment variables, you can yse the -Fc switch to get
|> C code produced from the standard output of CC, redirect this to a temporary
|> file and compile this.
[...]
|> There are some minor difficulies to be overcome.
[...}
|> 4.	Watch out for problems with include files. The only problem I had
|> 	was that SUN's ctype.h seems to be different from anybody else's.
|> 	This is a difference between the character table being defined
|> 	as _ctype_ in on and __ctype in another (or something like that).
|> 	However, your mileage may vary.
When I ported cfront to a new machine, I found the easiest way to handle
header file problems was to use the C header files from the target machine.
The same would probably be true when cross-compiling. Since cfront runs
after the pre-processor, all the includes are expanded by the time your
mangled c code is produced. (The C++ headers use the standard C headers
extensively.)

I would imagine you would also want to build the C++ library for the target
machine. A problem I have had here is the function memcpy is used in the
iostream classes. This is a Unix, rather than C, function as far as I can
work out, and is not even supported on all versions of Unix. Fortunately,
it's very simple to write your own.
-- 
Philip Machanick
philip@pescadero.stanford.edu