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**Greg Turgeon** · 10 Feb 2001, 03:58 PM

Code:

Scott--
   
I wrote a service last year using PB.  Here's what I found.
   
-- Sample BASIC code for services can be found in various places on 
the web, but problems exist with every example I looked at. Some was 
incomplete, some was buggy or flawed in fundamental ways, and all of 
it was a waste of my time to try to work with.  Microsoft makes 
available some very useful examples in C, which proved far more 
helpful to use as models. 
   
-- Technically, services are not supposed to offer a user interface.  
That's part of the whole idea behind a service as opposed to an 
application.  The service API wasn't designed with the thought that 
icons in the system tray would play any role in the way that a 
service is manipulated.  That doesn't mean that such a feature is 
impossible, but it does bring up the question of why a service, and 
not a application, is intended at all. (I'm hardly obsessive about 
always coloring within the lines.  I'm just pointing out that 
although services offer certain features that applications do not, 
the reverse is true as well.  I ended up writing a separate app to 
handle user communication with the service whenever doing so became 
necessary.) 
   
-- Of the books I examined on the subject, Kevin  Miller's 
[i]Professional NT Services [/i] (Wrox Press, 1998) offered the 
clearest, most practical guide.  I bought it and have never regretted 
the purchase. 
   
-- If you're wondering about threads and where something belongs, you 
probably will do well to dig up more information about this entire 
subject.  Writing a service poses interesting challenges, some of 
which have no parallel in other types of programming that I myself 
had ever done. 
   
-- Greg

[This message has been edited by Greg Turgeon (edited February 10, 2001).]

**Scott Wolfington** · 10 Feb 2001, 05:46 PM

Thanks Greg! I'll go check out that book. I found this article on
the MSKB too.

PRB: Common Controls Might Behave Unpredictably in an Interactive Service after Logoff http://support.microsoft.com/support.../Q238/7/21.ASP

"Implementing a user interface within a service process is not
recommended. Whenever possible, a service process should be
shielded from the actions of an interactive user. If a service
needs to receive input or display output to the interactive
user, a separate process should be implemented to run within
the same logon session as the interactive user. That process
can communicate with the service through the standard Win32
methods of interprocess communication."

Now I just need to figure out how to do "interprocess communication"
with PowerBASIC. My service writes log data to an output file, and if
the "user interface" (in this case a different app) is up, I'd like
to write the same log data to a LISTBOX on the user interface dialog,
so the user can monitor what's happening. What would be the best approach
for something like this?

Thanks,
Scott

------------------
Scott Wolfington
http://www.boogietools.com

[This message has been edited by Scott Wolfington (edited March 05, 2003).]

**Greg Turgeon** · 10 Feb 2001, 07:51 PM

Code:

Scott--
   
The task you describe obviously doesn't require tremendous 
speed, so I'd just have the service pass data to display to 
the interface app using %WM_COPYDATA.  Some time ago Semen 
posted code that illustrates using this method of 
interprocess communication.  It's relatively simple and can 
do the job well.
   
-- Greg

------------------
-- Greg
[email protected]

**Scott Wolfington** · 10 Feb 2001, 08:17 PM

Greg,

Once again, thank you. I'll give it a try. BTW, just got back from
the bookstore with my own copy of "Professional NT Services". It looks
pretty good.

Cheers,
Scott

------------------
Scott Wolfington
http://www.boogietools.com

[This message has been edited by Scott Wolfington (edited March 05, 2003).]

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