[Rcpp-devel] "const" not allowed for Matrix arguments?

[Romain Francois]

I've tried to be better about const-ness in revision 3986. Please keep 
investigating.

Thanks.

Romain

Le 16/11/12 19:53, Ramon Diaz-Uriarte a écrit :
>
> More on const arguments:
>
> the first will compile and work, the second will not compile, even if we
> do not modify anything. As far as I can tell, in this case the culprit is
> related to having the reference to the Column, because f3 does compile and
> work.
>
> I guess the problem is the "*this", returned by Column; is there another
> way of making sure the caller does not modify the matrix, while enjoying
> the usage of Column (and Row)?
>
> Best,
>
> R.
>
>
> // [[Rcpp::export]]
> int f1(Rcpp::IntegerMatrix m1) {
>    const Rcpp::IntegerMatrix::Column c1 = m1(_, 1);
>    int dd = c1[0] * 2;
>    return dd;
> }
>
> // [[Rcpp::export]]
> int f2(const Rcpp::IntegerMatrix m1) {
>    const Rcpp::IntegerMatrix::Column c1 = m1(_, 1);
>    int dd = c1[0] * 2;
>    return dd;
> }
>
> // [[Rcpp::export]]
> int f3(const Rcpp::IntegerMatrix m1) {
>    int dd = m1(0, 0) * 2;
>    return dd;
> }


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