DOS file locks (AREV Specific) [Revelation On-Line Wiki]

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At 13 MAR 1998 11:06:57AM louis wrote:

AREV Specific

Is there a way to lock a DOS file (in AREV Basic) before

using the OSOPEN/OSBREAD/OSWRITE type commands? We have

a DOS app that needs to read/delete shared files/records.

TIA

At 13 MAR 1998 02:08PM Victor Engel wrote:

Is there a way to lock a DOS file (in AREV Basic) before using the OSOPEN/OSBREAD/OSWRITE type commands? We have a DOS app that needs to read/delete shared files/records. TIA

OSOPEN opens the file with write access. Check STATUS() to see if another process already has the file open. The possible values for STATUS() are:

0 No error

1 Bad operating system filename

2 Access denied by operating system

4 File does not exist

5 Undefined error

If you still want to implement locking, you can. Just establish a standard that you will use. If you're using Netware, locks are handled by semaphores, so the file need not even exist. I'd suggest something like this:

OPEN 'DOS' to DOS_HANDLE THEN
 LOCK DOS_HANDLE, OS_NAME THEN
Put your opens, reads, etc. here ; don't forget to unlock
 END
END

Remember, DOS is an Arev file name with DOS filenames as its records.

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