AFAIK there is no such function. The fastest way I know is to issue a SQLSETPROP on a ReadOnly property and capture the error message. The following code executes quite fast:

LOCAL lcOldError, laHandles[1], lnHandles, lnI
PRIVATE plValid
plValid = .f.
lcOldError = ON('error')
ON ERROR GetError()
lnHandles = 0
FOR lnI = 1 to 255
    SQLSETPROP(lnI,"ConnectBusy",.t.)
    IF plValid
    	lnHandles = lnHandles + 1
    	DIMENSION laHandles[lnHandles]
    	laHandles[lnHandles] = lnI
    ENDIF
ENDFOR
ON ERROR &lcOldError
*!* do something with your laHandles array
SUSPEND
RETURN

PROCEDURE GetError
LOCAL lnError, laError[1]
AERROR(laError)
lnError = laError(1)
plValid = .f.
IF lnError = 1533  && "This property is read-only."
	plValid = .t.
ENDIF
*!*	Otherwise the error is 1466 "Connection handle is invalid."

>Hey all,
>
>For some reason I thought there was a function that would return an array of active SQL connection handles along with information about each connection. But I can't find anything in the docs in VFP 7.0 or 8.0...
>
>We have a function that checks for an existing connection, but it is slow in the event that no such connection exists (because it has to use SQLGETPROP() on all 255 possible handles to see if one exists). If there is a better way (such as the array I thought was available) it would be great to find something faster...
>
>Tell me what I'm missing, please! Thanks!
>
>JoeK