documentation of .C (PR#9948)
On Wed, 10 Oct 2007, schlather at math.uni-goettingen.de wrote:
Full_Name: Martin Schlather Version: R version 2.7.0 Under development (unstable) (2007-10-01 r43043) OS: Linux Submission from: (NULL) (91.3.209.203) Hi, There are 2 dangers with using 'DUP=FALSE' mentioned: * formal arguments * lists Would you also mention a third one, namely that values in R are now only referenced whenever possible and not always copied; hence .C(..., DUP=FALSE) may change the values of other local variables.
How about a warning like "if you pass a local variable to .C/.Fortran with DUP=FALSE, your compiled code can alter the local variable and not just the copy in the return list. " -thomas (copied from ?.C, of course)