anchor.diff:    !---------------------------------------------------------------------------------------------------------------------------------
     endfunction VTK_END
   
  -  !> @brief The VTK_INI_XML function is used for initializing file. This function must be the first to be called.
  +  !> @brief Function for initializing VTK-XML file.
     !> The XML standard is more powerful than legacy one. It is more flexible
     !> and free but on the other hand is more (but not so more using a library like @libvtk...) complex than legacy standard. The
  -  !> output of XML functions is a well-formated XML file at least for the ascii format (in the binary format @libvtk use
  +  !> output of XML functions is a well-formated XML file at least for the ascii format (in the binary format @libvtk uses
     !> raw-data format that does not produce a well formated XML file).
     !> Note that the XML functions have the same name of legacy functions with the suffix \em XML.
  -  !> @note An example of usage is: E_IO = VTK_INI_XML('BINARY','XML_RECT_BINARY.vtr','RectilinearGrid',
  -  !> nx1=nx1,nx2=nx2,ny1=ny1,ny2=ny2,nz1=nz1,nz2=nz2). \n
  +  !> @remark This function must be the first to be called.
  +  !> @note An example of usage is: \n
  +  !> @code ...
  +  !> integer(I4P):: nx1,nx2,ny1,ny2,nz1,nz2
  +  !> ...
  +  !> E_IO = VTK_INI_XML('BINARY','XML_RECT_BINARY.vtr','RectilinearGrid',nx1=nx1,nx2=nx2,ny1=ny1,ny2=ny2,nz1=nz1,nz2=nz2)
  +  !> ... @endcode
     !> Note that the file extension is necessary in the file name. The XML standard has different extensions for each
  -  !> different topologies (i.e. \em vtr for rectilinear topology). See the VTK-standard file for more information.
  +  !> different topologies (e.g. \em vtr for rectilinear topology). See the VTK-standard file for more information.
     !> @return E_IO: integer(I4P) error flag
     function VTK_INI_XML(output_format,filename,mesh_topology,nx1,nx2,ny1,ny2,nz1,nz2) result(E_IO)
     !---------------------------------------------------------------------------------------------------------------------------------
  
positive.code:   !---------------------------------------------------------------------------------------------------------------------------------
    endfunction VTK_VAR_TEXT_R4
  
    !>This function is used to finalize the file opened and it has not inputs; the @libvtk manages the file unit without the
    !>user's action.
    !> @note An example of usage is: E_IO=VTK_END().
    !> @return E_IO: integer(I4P) error flag
    function VTK_END() result(E_IO)
    !---------------------------------------------------------------------------------------------------------------------------------
  
negative.code:   !---------------------------------------------------------------------------------------------------------------------------------
    endfunction VTK_GEO_XML_CLOSEP
  
    !> Function that \b must be used when unstructured grid is used, it saves the connectivity of the unstructured gird.
    !> @note The vector \b connect must follow the VTK-legacy standard. It is passed as \em assumed-shape array
    !> because its dimensions is related to the mesh dimensions in a complex way. Its dimensions can be calculated by the following
    !> equation: \f$dc = dc = \sum\limits_{i = 1}^{NC} {nvertex_i }\f$.
    !> Note that this equation is different from the legacy one. The XML connectivity convention is quite different from the
    !> legacy standard. As an example suppose we have a mesh composed by 2 cells, one hexahedron (8 vertices) and one pyramid with
    !> square basis (5 vertices) and suppose that the basis of pyramid is constitute by a face of the hexahedron and so the two cells
    !> share 4 vertices. The above equation gives \f$dc=8+5=13\f$. The connectivity vector for this mesh can be: \n
    !> first cell \n
    !> connect(1)  = 0 identification flag of \f$1^\circ\f$ vertex of 1° cell \n
    !> connect(2)  = 1 identification flag of \f$2^\circ\f$ vertex of 1° cell \n
  