diff --git a/matlab/gdat.m b/matlab/gdat.m
index dfb5baf34196f96f8a7f41a86f6e0d11bb9ad44d..48b33aa419965375f6de1734a987a7dadbe85aab 100644
--- a/matlab/gdat.m
+++ b/matlab/gdat.m
@@ -15,9 +15,10 @@ function [gdat_data,gdat_params,error_status,varargout] = gdat(shot,data_request
 %    data_request: keyword (like 'ip') or trace name or structure containing all parameters but shot number
 %    varargin{i},varargin{i+1},i=1:nargin-2: additional optional parameters given in pairs: param_name, param_value
 %                                            The optional parameters list might depend on the data_request
-%              examples of optional parameters:
-%                               'plot',1 (plot is set by default to 0)
-%                               'machine','TCV' (the default machine is the local machine)
+%        examples of optional parameters:
+%            'doplot',1 (plot is set by default to 0)
+%            'machine','TCV' (the default machine is the local machine)
+%            'error_if_empty': 0 (no warning nor error if data is empty); 1 (warning if empty, default); 2 (error if empty)
 %
 % Outputs:
 %
@@ -91,7 +92,6 @@ if nargin>2
     end
   end
 end
-
 fusion_machine_defaultname=getenv('FUSION_MACHINE_DEFAULTNAME');
 default_machine = 'tcv';
 if ~isempty(fusion_machine_defaultname)