Re: rvalue

From: Keith Thompson (kst-u_at_mib.org)
Date: 04/09/04 

Date: Fri, 09 Apr 2004 05:55:54 GMT

Tobias Oed <tobias@physics.odu.edu> writes:
> Hi all, It's been a while!
> I'm working on a very buggy piece of code that uses a lot of macros.
> A bunch of them look like
> #define POSITION(mw,row) (mw.positions[row])
> In order to debug the thing I'd like to modify these macors so they
> can only be used as rvalues and not as lvalues. If they are used as
> lvalues I want my compililation to fail. Unfortunately I can't
> remember a nice way to do that.

Assuming the result is numeric, I think this will work.

#define POSITION(mw,row) (+mw.positions[row])

I usually prefer to enclose all reference to macro arguments in
parentheses to avoid operator precedence problems, but I don't *think*
it's necessary in this case (though it won't hurt to do it anyway). 

-- 
Keith Thompson (The_Other_Keith) kst-u@mib.org  <http://www.ghoti.net/~kst>
San Diego Supercomputer Center             <*>  <http://users.sdsc.edu/~kst>
Schroedinger does Shakespeare: "To be *and* not to be"

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