>I use the shellexecute class to open pdf files of drawings. Is there a way to tell when the file that shellexecute opens is closed?

I do the same thing although somewhat differently:

	IF FILE(pdffile)
		DO DECLexewait  && declares dlls

		lcresult = Acrofind() && locates acrobat reader

		IF EMPTY(lcresult)    && could not locate it

			*--Look for AcroRd32.exe first in the registry

			lcresult = readregistrykey()
			IF OCCURS('"',lcresult)>0
				IF TYPE('lcresult')="C" .AND. !EMPTY(lcresult)
					m.cAppName=SUBSTR(lcresult,2,AT('"',lcresult,2)-2)
				ELSE
					m.cAppName = ''
				ENDIF
			ELSE
				m.cAppName = lcresult+"AcroRd32.Exe"
			ENDIF
		ELSE
			m.cAppName = lcresult
		ENDIF
		IF FILE(m.cAppName)	&& AcroRd32.exe
			lcline = " /p /h "
			IF li_acordview	&& preview in acrobat reader so user can select printer by ctrl-p
				lcline = ""
			ENDIF

			SET DEFAULT TO LEFT(hdir,RAT("\",hdir)-1)
			lnpos=(RAT("\",m.cAppName)+1)	&& one position to the right of
			lcshort=''
			lcpath=''
			IF lnpos > 0
				lcshort = UPPER(SUBSTR(m.cAppName,lnpos))	&& grab from lnpos to end
				lcpath  = UPPER(LEFT(m.cAppName,RAT("\",m.cAppName)-1))			&& strip off the extension
			ENDIF

			IF !EMPTY(lcshort) .AND. !EMPTY(lcpath)
				lcpath = "'"+lcpath+"'"
				SET DEFAULT TO &lcpath
				llacordok = ExeWait(lcshort,lcline+hdir+xacordform+'.xfdf',lcpath)
			ELSE
				llacordok = ExeWait( m.cAppName, lcline+xacordform+'.xfdf',hdir)
			ENDIF

			IF !llacordok
				=MESSAGEBOX("Unable to print Acord Form.",0+16+4096,"ERROR")
			ELSE
				WAIT WINDOW "Finished Printing" NOWAIT
			ENDIF

			SET DEFAULT TO &lcACORDdef

		ELSE
			=MESSAGEBOX('Unable to locate Acrobat Reader. Please install and try again',0+16+4096,'ERROR - Acrobat Reader Missing.')
		ENDIF

		DO RELexewait
	
	ELSE
		=MESSAGEBOX("Unable to create Acord Form.",0+16+4096,"ERROR - PDF or XFDF Missing.")
	ENDIF


PROCEDURE DECLexewait  && load required dlls for exewait function

=ADLLS(dllarray)
IF ASCAN(dllarray,'CREATEPROCESS') = 0
	DECLARE INTEGER CreateProcess IN kernel32;
		INTEGER lpAppName, STRING lpCmdLine, INTEGER lpProcAttr,;
		INTEGER lpThrAttr, INTEGER bInhHandles, INTEGER dwCrFlags,;
		INTEGER lpEnvir, INTEGER lpCurDir, ;
		STRING @lpStInfo, STRING @lpProcInfo
ENDIF
IF ASCAN(dllarray,'GETLASTERROR') = 0
	DECLARE INTEGER GetLastError IN kernel32
ENDIF
IF ASCAN(dllarray,"CLOSEHANDLE") = 0
	DECLARE INTEGER CloseHandle IN kernel32 INTEGER hObject
ENDIF
IF ASCAN(dllarray,"GETEXITCODEPROCESS") = 0
	DECLARE INTEGER GetExitCodeProcess IN WIN32API INTEGER hProcess, INTEGER @lpExitCode
ENDIF
IF ASCAN(dllarray,"SLEEP") = 0
	DECLARE Sleep IN kernel32 INTEGER dwMilliseconds
ENDIF

RETURN


PROCEDURE RELexewait  && release dlls for exewait function

CLEAR DLLS CreateProcess
CLEAR DLLS GetLastError
CLEAR DLLS CloseHandle
CLEAR DLLS GetExitCodeProcess
CLEAR DLLS Sleep

RETURN


*--Uses GetExitcodeProcess instead of waitforsingleobject
PROCEDURE  ExeWait (lcApp, lcCmdLine, lcdir)
PRIVATE lntimes
lntimes = 0
IF _VFP.AUTOYIELD = .F.
	llsetback = .T.
ELSE
	llsetback = .F.
ENDIF
_VFP.AUTOYIELD = .T.
PRIVATE lnclosepass
lnclosepass = 0
#DEFINE INFINITE  0xFFFFFFFF
LOCAL lcStartupInfo, lcProcInfo, hProcess, ;
	lnPrio, lnIBelieve1
lnIBelieve1 = 1   && Don't remember what that was
lnPrio = 32 && Priority of Process=Normal
lcStartupInfo = CHR(68) + REPLI(CHR(0), 67)
lcProcInfo = REPLI(CHR(0), 16)
IF CreateProcess(0, m.lcApp+" "+m.lcCmdLine+CHR(0), 0,0,;
		m.lnIBelieve1, m.lnPrio,;
		0, 0, @lcStartupInfo, @lcProcInfo) <> 0
	* process and thread handles returned in ProcInfo structure
	hProcess = buf2dword(SUBSTR(lcProcInfo, 1,4))
	hThread = buf2dword(SUBSTR(lcProcInfo, 5,4))
	* waiting until the termination of the program
	DOEVENTS
	IF !li_acordview						&& printing only
		DO stopadobe
	ELSE
		DO WHILE .T.
			exitcode = 0					&& initialize return value to 0
			= GetExitCodeProcess(hProcess, @exitcode)	&& try to obtain process exit code
			IF exitcode # 259				&& not still busy
				EXIT							&& fall out of loop
			ELSE
				*--Attempt to close the password window up to 3 times
				IF dopass .and. lnclosepass < 3 .AND. PassWin('Password')
					= Sleep (1000)			&& wait 1 seconds
					lnclosepass = lnclosepass + 1
				ENDIF
			ENDIF
			= Sleep (100)					&& wait .1 seconds
		ENDDO
	ENDIF
	= CloseHandle(hThread)
	= CloseHandle(hProcess)
ELSE
	IF llsetback
		_VFP.AUTOYIELD = .F.
	ENDIF
	RETURN .F.
ENDIF
IF llsetback
	_VFP.AUTOYIELD = .F.
ENDIF
RETURN