% Purpose
%    loads the next data file for writing.
%
% Synopsis
%    mexeps('setnextw',data_file)
%
% Description
%    It loads (opens) the next data file for creating. The 
%    input argument data_file is the name of the data file.
%    The function mexeps('openw',pointer_file) must be called
%    first which opens a new pointer file. (At closing time,
%    the data_file will be listed to this pointer file by the
%    program.)
%
% Examples
%    Open a pointer file and set the next data file for writing
%
%	out_pointer='output.ptr'; 
%       out_datafile = 'ctd.cdf'
%       mexeps('openw',out_pointer);  
%       mexeps('setnextw',out_datafile);
%
% See Also
%    openw
%