% Purpose
%    opens an EPIC System file (netCDF file) for creating.
%
% Synopsis
%    mexeps('openw',pointer_file)
%
% Description
%    It opens a new EPIC System file for writing. The input
%    argument pointer_file is the pointer file which will 
%    contain a list of netCDF data file that will be created 
%    later.  To open the netCDF data file itself, 
%    mexeps('setnextw',...) must be called.
%
% Examples
%    out_pointer = 'output.ptr';
%    mexeps('openw',out_pointer); 
%
% See Also
%    setnextw, epsclose, openr, opene
%