Invalid custom display definitions

When reading the config file, SM_GUI will make a general check if each custom display definition follows the syntax described above. If not, that definition will be discarded right away (the program should still start properly). You will see a message in the IDL output log.

Then, each custom display definition is processed whenever a new file is read or a new scan is started. At this point, two things can go wrong:

• You have used detector names in the code which are not available for that file, because they have not been recorded.

• There is a general syntax error in the code.

SM_GUI can't distinguish between these two cases. In any case, this display will be skipped (won't be available) and an informational error message will be printed to the output log if you have set the variable custom_display_errormessage in the config file to 1 (see Sec. 5.20). Otherwise, the display combination will be disregarded silently.

Warning: SM_GUI uses the IDL execute function to execute a statement like

    image = code

and of course it is not hard to write a code which will cause an error. As noted above, in most cases this error should be caught and handled gracefully. Still, it is well possible that you write something which brakes and crashes the program. Better know what you are doing.