If the form is created as a class (In PRG or VCX) the this code not works.
But You can define some variable & then store a vlaue in Unload event of the form:

LOCAL oObj
PRIVATE nRetVal
nRetVal = 0
oObj=CREATEOBJECT("frmTeste",1,"")
oObj.Show()

** In Unload event, put
  nRetVal = 150
** Then
? nRetVal