[R] R matrices in memory

[Francisco J Molina]

Acording to the documentation in gsl 

"The physical row dimension tda, or trailing dimension, specifies the size
of a row of the matrix as laid out in memory"

I think that if I pass a matrix to C++ through .C as single ( or.double ),
that is, 

.C ( as.single ( matrix ))

then the tda is simply the number of elements of that matrix.
Am I right?

Thank you.