samer@0: function [p,h]=dbroot(newroot, newhost)
samer@0: % dbroot - Set or retrieve Matbase root directory
samer@0: %
samer@0: % dbroot :: unit -> string ~'current root', string ~'current name'.
samer@0: % dbroot :: string ~'new root' -> action unit.
samer@0: % dbroot :: string ~'new root', string ~'new host' -> action unit.
samer@0: %
samer@0: % The matbase system uses the root and host name to decided where to
samer@0: % put the MAT files saved by dbsave, dbsaveas and dbtmp. A directory named
samer@0: % after the host is created under the given root. Directories based on
samer@0: % the current date are created under the per-host directories. This means
samer@0: % the root can be on a shared filesystem as long as each host has a unique
samer@0: % name.
samer@0: %
samer@0: % Note that dbroot MUST be called at least once before the matbase is used
samer@0: % otherwise the results are undefined.
samer@0: %
samer@0: % If no hostname is given, dbroot will attempt to read the HOSTNAME
samer@0: % environment variable. If this is empty, a error will be raised.
samer@0: 
samer@0: global DBROOT
samer@0: global HOSTNAME
samer@0: 
samer@0: if nargin>=1, 
samer@0: 	DBROOT=newroot; 
samer@0: 	if nargin<2, newhost=getenv('HOSTNAME'); end
samer@0: 	if isempty(newhost)
samer@0: 		error('dbroot:nohostname','Could not get host name');
samer@0: 	end
samer@0: 	HOSTNAME=[newhost filesep]; 
samer@0: else
samer@0: 	% no input arguments so return current values
samer@0: 	p=DBROOT;
samer@0: 	h=HOSTNAME;
samer@0: end
samer@0: 
samer@0: