Checking for Errors
Use the inquire_4gl statement to check for errors resulting from the exec 4gl statements. By default, any such errors are displayed on the screen. To turn off the display of these errors, use the set_4gl statement with the messages keyword.
Neither the global error handler that set_sql defines nor the sql whenever statement apply to exec 4gl errors. An error handler specified with the iiseterr function is not called when an error occurs.