\name{RcppVector}
\alias{RcppVector}
\alias{RcppMatrix}
\alias{RcppStringVector}
\alias{RcppVectorExample}
\title{C++ classes for receiving R object in C++}
\description{
  \code{RcppVector}, \code{RcppMatrix} and \code{RcppStringVector} are
  C++ classes defined in \code{Rcpp.h} that can
  pass vectors (matrices) of \R objects of appropriate types to C++ via
  the \code{.Call()} function interface. 
  
  The vector and matrix types are templated and can operate on \R types
  \code{intger} and \code{numeric}. 
  
  Member functions are provided to query the dimension of the vector or
  matrix object, convert it in a corresponding \code{C} representation,
  and also to convert it into a corresponding STL object.

}
%\usage{
%}
%\arguments{
%}
%\value{
%  Internal to the C++ code.
%}
\details{
  Usage of \code{RcppVector}, \code{RcppMatrix} and
  \code{RcppStringVector} in \code{C++} is fully defined in
  \code{Rcpp.h}. 

  As example, consider a call from \R to \code{C++} such as

  \preformatted{
  # an R example passing one type of each class to a function
  # someFunction in package somePackage
  val <- .Call("someFunction",
               rnorm(100),        # numeric vector
	       sample(1:10, 5, TRUE)  # int vector
	       search(),          # character vector
	       as.matrix(rnorm(100),10,10), # matrix
   	       PACKAGE="somePackage")
  }

  At the \code{C++} level, the corresponding code to assign these parameter to
  \code{C++} objects is can be as follows (taken from the C++ source of
  \code{RcppExample}):
  \preformatted{%
  SEXP someFunction(SEXP nvec, SEXP ivec,
                    SEXP svec, SEXP nmat) {

    RcppVector<double> nv(nvec);  		      
    RcppVector<int>    iv(ivec);
    RcppStringVector   sv(svec);
    RcppMatrix<double> nm(nmat);
  }
  }

  These \code{C++} objects could then be queried via
  \preformatted{%
    int n = nv.size();
    int d1 = nm.dim1(), d2 = nm.dim2();
  }
  to retrieve, respectively, vector length and matrix dimensions.

  Moreover, the \code{stlVector()} and \code{stlMatrix()} member
  functions can be used to convert the objects into STL objects:
  \preformatted{%
    vector<int> ivstl = iv.stlVector();
    vector< vector< double > > = nm.stlMatrix();
  }

}
%\references{
%  See \code{Rcpp.h} and the package vignette.
%}
\seealso{
  \code{RcppExample}, the vignette \dQuote{RcppAPI}.
}
\author{Dominick Samperi wrote most of Rcpp during 2005 and 2006.  Dirk
  Eddelbuettel made some additions, and became maintainer in 2008.}
\examples{
# set up some value
vector <- (seq(1,9))^2

# call the underlying  C++ function
result <- RcppVectorExample(vector)

# inspect returned object
result
}
\keyword{programming}
\keyword{interface}