Re: [Boost-users] Using boost interprocess file_lock.timed_lock

Subject: Re: [Boost-users] Using boost interprocess file_lock.timed_lock
From: Ion Gaztañaga (igaztanaga_at_[hidden])
Date: 2011-07-30 04:53:13

El 30/07/2011 9:58, Bill Moo escribió:
> On Fri, Jul 29, 2011 at 8:42 AM, <Viatcheslav.Sysoltsev_at_[hidden]
> <mailto:Viatcheslav.Sysoltsev_at_[hidden]>> wrote:

This is a Boost.Interprocess bug that I don't think it can be easily 
solved. Once you lock a file in Windows, you can only write to it 
through the handle (internal to fileLock) used to lock it. That's why 
the handle inside "os" is blocked. I should note this in the 
documentation as file locking can only be used portably in Interprocess 
to control access to ANOTHER file (or resource) but not to limit access 
to the same file you've just locked. From MSDN:

http://msdn.microsoft.com/en-us/library/aa365203%28v=vs.85%29.aspx

"Locking a region of a file is used to acquire shared or exclusive 
access to the specified region using this file handle. If the file 
handle is inherited by a process created by the locking process, the 
child process is not granted access to the locked region. If the locking 
process opens the file a second time, it cannot access the specified 
region through this second handle until it unlocks the region."

Best,

Ion