>I'm trying to find a way to be sure that only one instance of my foxpro application is running. So when i start the application a second time, i want to show the user a message.
>
>Ok I know there is an api call witch compares the captions of running application, but I don't whant to use that because an other application or a mail message can have the same caption.
>
>Thanks.
>
>Gerben.

My colleague implemented the following code:

* -- NSL 6/6/01  Check to see if there are other copies of JC instanciated
*--------------------------------------------------------------------------
PRIVATE lcLibrary,GetWind
lcLibrary=SET('LIBRARY')
SET LIBRARY TO sys(2004)+"foxtools.fll" ADDITIVE
GetWind=RegFn("FindWindow","CC","I")
wclass=0  
winName=Left(_screen.caption,len(_screen.caption)-1)  && Trim off the colon  - findwindow did not like that.
apphand=CallFn(GetWind,wclass,winName)

IF apphand<>0
	=mymessage('There is already a version of job control running from this machine.'+chr(13)+;
			'Only one version of JC can be running at a time.')
	close all
	clear all
	on error
*!*		if type('cOldScreenCaption')='C'
*!*	 		 _screen.caption=cOldScreenCaption
*!*		endif  
	clear events
	clear
	set sysmenu to default
	* Exit out of VFP
	RETURN
ENDIF
Modify Window screen TITLE winName
SET LIBRARY TO &lcLibrary

But I would not recommend it. Check API section here for the Ed Rauh's CreateEvent example.