[Rd] allocating character string of given size for .C

[Duncan Murdoch]

On 8/2/2006 11:08 AM, 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).
> 
> 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.

If you are unsure of the length of the message that you want to return, 
you can use R_alloc in C to allocate a buffer, and you don't need to 
worry about disposing of it:  it will be garbage collected.

Duncan Murdoch