Foxpro doesn't open files, Windows does. And there can be a big stack of filter drivers in play from AV and other things.
-- Alan Bourke alanpbourke (at) fastmail (dot) fm On Tue, 8 Mar 2016, at 05:46 PM, AndyHC wrote: > As Christof said some years ago: all is not what it seems with Foxpro > file handling - there is a *lot* of smoke and mirrors! > > On 08/03/2016 20:44, Tracy Pearson wrote: > > I have been tracking down a very random occurrence of a table opened with > > the Exclusive flag throwing an error. > > > > #111 Cannot update the cursor "cursor", since it is read-only. > > > > I checked the code, no NOUPDATE flag. > > > > I brought up SysInternals Process Monitor and opened, appended a record, > > and closed a table 10000 times. > > I had suspected multiple anti-virus and on demand backup tools causing > > behavior problems. > > This Windows 7 (virtual machine) has 1 GB RAM, Kaspersky, Bitdefender, and > > Carbonite installed. > > No exclusions, and Carbonite is set to specifically backup the data folder > > on demand. > > > > My test actually does a Try/Catch around the USE statement, wrapped in a DO > > WHILE NOT USED() > > It seems the tools mentioned are not the direct culprit. Instead when things > > fail, Windows Explorer was the direct cause. Windows Explorer opens the > > table Read Only and with Share Read/Write and reads the first 4000 bytes. > > Then closes the file. Why I don't know, I don't care. I do know it only > > happens when the Explorer window is open to the folder where the table > > exist. > > > > Lucky for me, the place I open tables is via a class, so a check with > > ISREADONLY() will prevent this in the future. > > > > So what really happens? In Process Monitor I can clearly see I open a table > > in one session of VFP 9, then in another session of VFP 9 I attempt to open > > it again. First VFP attempts to open the table Read/Write with Share None. > > It gets a Sharing Violation. Then VFP attempts to open the table Read Only > > with Share None. There is that split moment on some machines that VFP is > > successful. > > > > Has anyone else seen this behavior before? > > > > Thank you for reading, > > Tracy > > > > [excessive quoting removed by server] _______________________________________________ Post Messages to: [email protected] Subscription Maintenance: http://mail.leafe.com/mailman/listinfo/profox OT-free version of this list: http://mail.leafe.com/mailman/listinfo/profoxtech Searchable Archive: http://leafe.com/archives/search/profox This message: http://leafe.com/archives/byMID/profox/[email protected] ** All postings, unless explicitly stated otherwise, are the opinions of the author, and do not constitute legal or medical advice. This statement is added to the messages for those lawyers who are too stupid to see the obvious.
