multiple file access in CISAM

I'm in the process if attempting an integration of the Informix CISAM file drivers into another product and have a few questions that I'm sure the net can answer. If a file is being accessed at more than one point is there an easy way to synchronize the accessing? Is it possible to save isrecnum following access and use that to start a *logical* access on another isfd? It appears that isstart() may be called to set the physical record number, is it possible and reasonable to continue a logical access following that access?. If the foregoing is possible, what happens if the record pointed to by the saved isrecnum is removed or modified in the meantime? If the file is being accessed using 2 different isfds will record locking function between the 2 handles? Is it possible that accessing a record locked on one channel using the second channel will block? Could it free? -- Russ Kepler, Basis International Ltd. russ@bbx.basis.com phone: 505-345-5232