[Rd] Summary: too many arguments in foreign function call

Peter Dalgaard BSA p.dalgaard@biostat.ku.dk
18 Jul 2001 20:26:28 +0200

"Warnes, Gregory R" <gregory_r_warnes@groton.pfizer.com> writes:

> 6) I still feel that it is a reasonable change to increase the number of
> permitted arguments, at least to the same limits (whatever they are) imposed
> by S-Plus.  This seems simpler than telling users that as soon as they hit
> 65 arguments they have to change their code or learn a new interface
> mechanism.

I think you missed one point that John was making: "N++". There has to
be a limit to the number of arguments, C does not allow you to code
anything else portably. Whatever limit we choose, someone is going to
bump into it sooner or later, and we can't just increase the limit
every time.  

Then there's the problem of portability between compilers. A little
Web search reveals that the minimum maximum number (sic) of arguments
that a C compiler may impose according to the C standard is 31. So
there may already be standards-compliant C compilers that cannot
compile R. Obviously none of those have appeared within our user

That being said, I think 65 is a pretty weird limit to have. 2^N-1
would be a more obvious guess at a potential hard limit. So, since
we're already past 63, how about having a quick round of testing among
the R-devel readers to check out whether any of their systems would
break from inserting a limit of 127 or 255?

   O__  ---- Peter Dalgaard             Blegdamsvej 3  
  c/ /'_ --- Dept. of Biostatistics     2200 Cph. N   
 (*) \(*) -- University of Copenhagen   Denmark      Ph: (+45) 35327918
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