Re: opening twice with O_RDWR

[Mike - EMAIL IGNORED]

On Sun, 31 Dec 2006 11:48:07 -0800, Paul Pluzhnikov wrote:

> Mike - EMAIL IGNORED <m_d_berger_1900@yahoo.com> writes:
> 
>> Since in my case, a preexisting file does not mean a failure, this
>> will not serve unless I use a second "locking file".  I quick test
>> has verified this. If, in the above, the word "exists" were changed
>> to "opened", my purpose would be served.
> 
> What exactly *is* your purpose?
> 
> If it is "fail second open of the same file", then just keep track
> of already opened files in your program.
> 
> From the OS stand point it is perfectly acceptable and valid to
> have the same file opened multiple times, and it is unreasonable
> to expect that it will keep track of which files you've already
> opened for you ...
> 
> Cheers,

My purpose is not relevant, but I assure you that the requirement
is correctly stated.  I confirmed that I can open the file O_RDWR
simultaneously from two processes.  Seems to me like a good way to
make a mess of a file.  I guess I will use a locking file opened
from a singleton.

Mike.