[Gretl-users] Error messages from inside functions

I am writing a function that, when used with some bad input variables, breaks with the following error message: No observations would be left! I would prefer to have the possibility to a) Prevent these error messages from the output and instead provide my own error message, e.g. funcerr "ERROR: No observations left!" or, if this is not possible, b) prevent the error message ">> smpl group != groupremove_k --restrict" from the output and only have the output "No observations would be left!". How should I do this in a gretl function? Best regards Andreas