It is possible to display an error message and abort execution in Simulink using the ERROR function.
One can check for the validity of the dialog input in the mask initialization commands section and invoke the ERROR function with a desired error message if the input is found to be invalid. For example, if the dialog parameter is stored in the variable errID and is invalid if it is greater than 100, then the initialization section can have the following code:
if(errID >100)
error('The error ID is too large');
end
