On Wed, 2 Aug 2006, Tamas K Papp wrote: > Hi, > > I have a C function (called via .C) which returns (by writing into > buffers) some values of known (or fixed) length, all of these are > numerical so I can allocate storage for them via as.double() and > as.integer(). > > However, there is a potential error message that I would like to > return into a char * buffer [1]. How can I allocate it in R (eg > something similar to as.integer(), but taking the number of > characters).
It's a long time since I have done that, but AFAIR in S you needed to pass a length-one character vector containing a string of the appropriate maximal length. In R it is a little simpler: you are given a char** pointer p, and when returning from C, .C() copies the valued pointed to by p[i] to the ith element of a character vector via mkChar. So you need to pass a length-one character vector with anything in the first element, e.g. character(1). > I would like to avoid .Call if possible, this is the only tricky > argument. > > Thanks, > > Tamas > > [1] I would of course use strncpy to avoid overflows. -- Brian D. Ripley, [EMAIL PROTECTED] Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/ University of Oxford, Tel: +44 1865 272861 (self) 1 South Parks Road, +44 1865 272866 (PA) Oxford OX1 3TG, UK Fax: +44 1865 272595 ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
