@param v pointer to a vector
@param length_increment length increment in elements
@param data_bytes requested size in bytes
@param header_bytes header size in bytes (may be zero)
@param data_align alignment (may be zero)
@param v pointer to a vector
@param length_increment length increment in elements
@param data_bytes requested size in bytes
@param header_bytes header size in bytes (may be zero)
@param data_align alignment (may be zero)