[Rd] SEXP size management.

[Charles Danko]

Hi,

Trying to decrease the size of a SEXP variable without reassigning
values individually in a loop.

So far, I've tried using Realloc, as the follow source demonstrates:
SEXP dothis() {
        SEXP Rblah;
        PROTECT(Rblah = NEW_INTEGER(6));

        int* blah = INTEGER(Rblah);
        blah[0] = 1;
        blah[1] = 2;
        blah[2] = 3;

        Realloc(Rblah, 3, INTEGER);

        UNPROTECT(1);
        return(Rblah);
}

According to the documentation, I think that this should work, however
it returns an error on compile: "test.c:17: error: expected expression
before ')' token" (line 17 refers to the Realloc line).

Another solution that will suit my needs is managing the variable in C
and assigning the pointer to an R type in the end.  The following code
gets at this, but int* and SEXP, INTEGER are incompatible:
SEXP dothat() {
        int* blah = malloc(3);// = INTEGER(Rblah);
        blah[0] = 1;
        blah[1] = 2;
        blah[2] = 3;

        SEXP Rblah;
        PROTECT(Rblah = blah);

        UNPROTECT(1);
        return(Rblah);
}

Any suggestions for someone still new to SEXP memory management?

Thanks,
Charles

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