On 16/05/2014 11:06, Duncan Murdoch wrote:
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.
('Yes on a 64-bit platform.') The type for a vector length is R_xlen_t,
e.g. allocVector is declared as
SEXP Rf_allocVector(SEXPTYPE, R_xlen_t);
That is never 'long long int' ....
Duncan Murdoch
Thank you again, in advance,
Adrian
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Brian D. Ripley, rip...@stats.ox.ac.uk
Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/
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