Hi,

>This *was* my understanding about timers: A timer does not fire during a SELECT-SQL and a next line that tests for the _TALLY. It only fires on moments that an input (most notably from a user) is possible.
>
>As a consequence of that understanding, there is *no* need to save/restore _TALLY in the timer event's code.
>
>This is about to become my understanding about timers: If _vfp.autoyield=.T. a timer can also fire after a SELECT-SQL and before the next line that tests for the _TALLY.
>
>As a consequence of that understanding, there *is* a need to save/restore _TALLY in the timer event's code.
>
>I'm now searching affirmation of my new understanding here.

Well here's a crude test:

DEFINE CLASS form1 AS form


	Top = 0
	Left = 0
	DoCreate = .T.
	Caption = "Form1"
	Name = "Form1"


	ADD OBJECT timer1 AS timer WITH ;
		Top = 24, ;
		Left = 36, ;
		Height = 37, ;
		Width = 61, ;
		Name = "Timer1"


	ADD OBJECT command1 AS commandbutton WITH ;
		Top = 36, ;
		Left = 204, ;
		Height = 37, ;
		Width = 73, ;
		Caption = "Command1", ;
		Name = "Command1"


	PROCEDURE timer1.Timer
		this.Enabled = .F.
		SELECT id FROM Table1 WHERE id <> 1 INTO CURSOR j
                * _tally: 50
		this.Enabled = .T.
	ENDPROC


	PROCEDURE command1.Click
		Application.AutoYield = .T.
		thisform.timer1.Interval = 100
		thisform.timer1.Enabled = .T.
		FOR x = 1 TO 100000
		  SELECT id FROM Table1 WHERE id = 1 INTO CURSOR viv
                  * _tally: 1
		  DOEVENTS   && No problem if this is not here
		  IF _tally <> 1
		    SET STEP ON 
		  ENDIF
		ENDFOR
		=MESSAGEBOX("Done")
	ENDPROC
	
ENDDEFINE

Only fails if the 'DOEVENTS' is immediately after the 'SELECT' and AutoYield's true. Doesn't ness. prove anything tho....
Regards,
Viv