File locking is impossible in Windows? SOLUTION

[elbertlev at hotmail.com]

Sure it will do if one of the processes needs read access only.

Scenario when you need shared rw acces with locking:
In the file you have "records" say 30 bytes long, 2 processes are
reading/writing these records by: lock-read-unlock or lock-write-unlock
. Both processes have to open the file with rw access and the third
process can overwrite the locked file. Actually the common method to
prevent file from been overwritten is: lock the region outside the
file. Such feacure is added to lock/unlock namely for this purpose.

You found the bug in WIN32.

In fact the file locked and overwritten hav ALL BYTES ZERO and the
length of the copyed file.