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.
On Thu, Mar 27, 2014 at 5:39 PM, Steven Watanabe
AMDG
On 03/27/2014 01:21 AM, Elad Moshe wrote:
Hi, this is my first post here so please bare with me :) . I recently used upgrade_lock to try access a shared resource from 2 different threads. I noticed that once the first thread acquired its upgrade_lock the second thread was blacked until the first thread unlock it. can someone please explain me the logic behind this behavior? isn't an upgrade lock just a shared_lock that can be upgraded to unique_lock? why not let both threads acquire it just like shared_lock until, and if, they decide to upgrade it to unique_lock?
If both threads tried to upgrade, you would have a deadlock.
In Christ, Steven Watanabe
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