Using rev with -ui flag

[J. Landman Gay]

Ben Rubinstein wrote:
> I have a number of questions - answers to any or 
> all would be gratefully received, as would any other relevant 
> observations or suggestions.
> 
> 
> * Is the -ui flag documented anywhere?  I can only find references from 
> users on various forums and lists - nothing from RR

I thought it was mentioned in the engine change log when it first 
appeared but now I can't find it. Mark Waddingham has confirmed that 
it's what to use in some posts on the improve list, I think. At any 
rate, I know it's the official "right way" to do it.

> 
> * Evidently the -ui flag implies don't start the GUI; does it have other 
> implications?

Not that I know of.

> 
> * Is there a way for a stack to tell that it's in "-ui" mode?  The flag 
> doesn't appear in the $0, $1 etc globals

The "environment" variable will be "command line". That isn't documented 
either; I found out by testing.

> 
> My app already has an "unattended" mode in which it is invoked from the 
> command with some additional parameters, and then (although still 
> normally displaying the UI) it goes through a sequence automatically, 
> and then automatically quits.  I expect it also to write some note to 
> stderr. Launching this with the -ui option it is totally silent, and it 
> does not appear to do anything, nor does it quit.  I've made a minimal 
> stack that just writes some notes to the console and then quits - that 
> works as expected in the -ui mode.  I'm guess that this means that my 
> real app is doing something during startup which is illegal in -ui mode; 
> therefore it throws an error and never gets to write anything to console 
> or to quit.

If there's a problem, it should show up in the error log.

> 
> * Are there known gotchas, things that you mustn't do in -ui mode?

Not really; some gui-related things won't work but you'll usually get an 
error in that case. Most things behave as you'd expect.

 From my CGI tutorial:

Some native Revolution commands that don't work (and may hang your 
script) are:

     * go - requires a GUI window redraw
     * toplevel - GUI-based
     * modeless (or any other stack modes) - GUI-based
     * create stack (or any file creation) - CGI permissions restriction
     * save stack (errors with "can't open stack backup file") - 
permissions restriction
     * beep - GUI-based


-- 
Jacqueline Landman Gay         |     jacque at hyperactivesw.com
HyperActive Software           |     http://www.hyperactivesw.com