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

Duncan Murdoch murdoch@stats.uwo.ca
Wed, 18 Jul 2001 14:52:54 -0400

>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? 

I'd guess there are different ways this could fail.  

1. The compiler might have a hard-coded upper limit on the number of
arguments to a function.
2. It might have an upper limit on the number of bytes of code
generated in a function, or in an object file. 

With 255 as the upper limit, the functions do_dotcall and do_dotCode
in dotcode.c will both be huge, so they might trigger the second kind
of failure. (I'd guess that no 16 bit compiler could handle them, for
instance, but nobody is compiling R on one of those.) It's probably
worth putting together a new dotcode.c version for people to test, not
just ask them to test for the first kind of failure.

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