Re: [Boost-users] [Thread] why isn't it possible to acquire 2 different upgrade_lock from 2 different threads?

Subject: Re: [Boost-users] [Thread] why isn't it possible to acquire 2 different upgrade_lock from 2 different threads?
From: Steven Watanabe (watanabesj_at_[hidden])
Date: 2014-03-27 13:11:43

AMDG

On 03/27/2014 09:09 AM, Elad Moshe wrote:
>> If both threads tried to upgrade, you would have a deadlock.
> 
> But how is it possible? isn't the upgrade operation atomic?
> if the 2 threads try to upgrade, one will succeed and the other one will
> block until the first thread will unlock.
> 

If it worked this way, it would mean that upgrade
lock would not exclude concurrent writes, which
completely defeats the point of using it in the
first place.

In Christ,
Steven Watanabe