+_GLIBCXX_BEGIN_NAMESPACE(std)
+
+ /**
+ * @addtogroup numeric_arrays
+ * @{
+ */
+
+ /**
+ * @brief Class defining multi-dimensional subset of an array.
+ *
+ * The slice class represents a multi-dimensional subset of an array,
+ * specified by three parameter sets: start offset, size array, and stride
+ * array. The start offset is the index of the first element of the array
+ * that is part of the subset. The size and stride array describe each
+ * dimension of the slice. Size is the number of elements in that
+ * dimension, and stride is the distance in the array between successive
+ * elements in that dimension. Each dimension's size and stride is taken
+ * to begin at an array element described by the previous dimension. The
+ * size array and stride array must be the same size.
+ *
+ * For example, if you have offset==3, stride[0]==11, size[1]==3,
+ * stride[1]==3, then slice[0,0]==array[3], slice[0,1]==array[6],
+ * slice[0,2]==array[9], slice[1,0]==array[14], slice[1,1]==array[17],
+ * slice[1,2]==array[20].
+ */
+ class gslice
+ {
+ public:
+ /// Construct an empty slice.
+ gslice();
+
+ /**
+ * @brief Construct a slice.
+ *
+ * Constructs a slice with as many dimensions as the length of the @a l
+ * and @a s arrays.
+ *
+ * @param o Offset in array of first element.
+ * @param l Array of dimension lengths.
+ * @param s Array of dimension strides between array elements.
+ */
+ gslice(size_t, const valarray<size_t>&, const valarray<size_t>&);
+
+ // XXX: the IS says the copy-ctor and copy-assignment operators are
+ // synthesized by the compiler but they are just unsuitable
+ // for a ref-counted semantic
+ /// Copy constructor.
+ gslice(const gslice&);
+
+ /// Destructor.
+ ~gslice();
+
+ // XXX: See the note above.
+ /// Assignment operator.
+ gslice& operator=(const gslice&);
+
+ /// Return array offset of first slice element.
+ size_t start() const;
+
+ /// Return array of sizes of slice dimensions.
+ valarray<size_t> size() const;