On 16/05/2014, 4:16 AM, Adrian Dușa wrote:
Dear list,

On a follow up from my previous email, I am now trying to allocate vectors
of length larger than 32-bit in C.

From the R internals documentation, I read that:
"The sxpinfo header is defined as a 32-bit C structure..."
and
"A SEXPREC is a C structure containing the 32-bit header..."

The question is: does the INTSXP allow vectors larger than 32-bit?


A test example:

//###
int *p_temp;

SEXP root = PROTECT(allocVector(VECSXP, 5));

long long int verylargeinteger;
// something to compute verylargeinteger, > 32-bit

SEXP temp = SET_VECTOR_ELT(root, 0, allocVector(INTSXP, verylargeinteger));
p_temp = INTEGER(temp);
//###

"temp" should be a vector of length > 32-bit, and "p_temp" should be the
pointer to that vector.

If declaring:
long long int *p_temp;
(but the compiler throws a warning with an incompatible pointer type,
because pointers should be integers of course).

I've looked at all SEXPTYPEs in the R internals, and the only one specific
to integer vectors is INTSXP. Can this be used for vectors of length larger
than 32-bit?

Yes, see the section on "Long Vectors" in chapter 12.

Duncan Murdoch


Thank you again, in advance,
Adrian



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