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POSTL and multithread
 

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    <p>I'm aware, that I need to use mutex, when I perform operations on single STL container inside multiple threads. However I want to know if there are any exceptions from this rule. Please consider simplified scenario I'm trying to implement.</p> <p>I have multiple threads adding elements to container and operation is surrounded with mutex lock/unlock. Then threads notify somehow (e.g. using eventfd on linux) single thread dedicated to dispatch elements in this container. What I want to do is to access first element in container without using mutex. Sample code based on deque but note that I ca use any container with queue capability:</p> <pre><code>std::mutex locker; std:deque&lt;int&gt; int_queue; int fd; // eventfd eventfd_t buffer; bool some_condition; </code></pre> <p>Thread 1, 2, 3, etc.</p> <pre><code>locker.lock (); int_queue.push_back (1); locker.unlock (); eventfd_write (fd, 1); </code></pre> <p>Thread dedicated to dispatch elements:</p> <pre><code>while (true) { bool some_condition (true); locker.lock (); if (int_quque.empty () == false) { locker.unlock (); } else { locker.unlock (); eventfd_read (fd, &amp;buffer); } while (some_condition) { int&amp; data (int_queue.front ()); some_condition = some_operation (data); // [1] } locker.lock (); int_queue.pop (); locker.unlock (); } </code></pre> <p>[1] I will do some_operation() on signle element many times, that's why I want to avoid mutex locking here. It's to expensive.</p> <p>I want to know if this code can lead to any synchronisation problems or something.</p>
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    1. COThere's no `stl::mutex` or `stl:deque` -- what compiler/library/standard are you referring to?
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    2. COSorry I meant "std", fixed.
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    3. CONo shortcuts, locking is required here.
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