[Spread-users] Question about thread-safety
george at omniti.com
Mon Jun 16 17:47:45 EDT 2003
On Monday, June 16, 2003, at 05:38 PM, John Schultz wrote:
>>> NOTE: if anyone knows how to instruct Unix/Linux systems not to reuse
>>> file descriptor IDs in a process, could you please email me or the
>>> a good reference (with page #)? Thanks!
>> It is part of the guaranteed semantics of open() that it returns the
>> lowest available file descriptor, so there's definitely no way to do
>> this unless you simply keep it open.
> Doesn't this cause a general race condition in multi-threaded
> applications that open and close file descriptors in multiple threads?
> The race condition: a thread is about to operate on file descriptor x,
> just before it does another thread(s) close x and create a new file
> descriptor which is assigned the same value as x.
> To avoid this race condition wouldn't all calls that create and/or
> file descriptors have to be done in a single thread that ensures no
> threads are operating on any file descriptors it is about to close? If
> that seems like a BAD thing to me.
Why can't you use a mutex to protect these sorts of accesses?
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