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From: agn@unh.cs.cmu.edu (Andreas Nowatzyk)
Newsgroups: comp.lang.c++
Subject: Re: goodbye cpp ??? (macros vs. inline functions)
Message-ID: <3663@pt.cs.cmu.edu>
Date: 22 Nov 88 17:32:20 GMT
References: <6590072@hplsla.HP.COM> <1757@dataio.Data-IO.COM> <3637@pt.cs.cmu.edu> <1304@cod.NOSC.MIL>
Organization: Carnegie-Mellon University, CS/RI
Lines: 36


In article <2191@pt.cs.cmu.edu> mball@cod.NOSC.MIL (Michael S. Ball) writes:
> ... If
> a particular C compiler can't produce good code from comma expressions,
> prehaps you should get a better one.  Better yet, look at some other
> implementations of C++ and see what they do. ...
>
Sure: get a better compiler is the universal answer. Unfortunately that
isn't a viable option in many cases (like in this one).
The point is: a macro gives you more controll over what is going on,
inline functions don't and there are cases where you need precise control.

> Huh!  I don't know what you mean by "troublesome nesting", but you can
> certainly have inline functions without return values.  The decision not to
Inline functions cannot use functions that have no return-value (a
side-effect of using comma-expressions). Inline functions calling other
inline function sometimes inline, somethimes thay don't. Exactly when
each case happens is rather arbitrary.


>The only way an inline function can tell the line number at a call
>is to pass the line number as a parameter to the function, in which
>case it will work whether expanded or not.  Inline function processing is
>done long after preprocessing, which is where the line number is known.
Not so fast: the problem is instrument a piece of code whitout changeing
it. Whenever that application code is dealing with the simulated environment,
the simulator need to know about it. It is possible to do that in C++,
but the details are quite messy and involve operator overloading, the
use of non-trivial macros and some other stuff.

  --  Andreas
-- 
   --  Andreas Nowatzyk  (DC5ZV)

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