Slight rewrite in C/C++ multi-threading to emphasize that to be a useful threading construct in most cases, it must offer atomic semantics and also memory ordering guarantees. Atomic does not imply memory ordering e.g. fences, and fences do not imply atomic. Not-atomic simply means that you might observe word tearing. You need fences on top of avoiding word-tearing to be a useful threading construct in most cases.
It is a common misconception that the <code>volatile</code> keyword is useful in portable [[thread (computing)|multi-threading]] code in C and C++. Unlike the [[Java (programming language)|Java]] and [[C Sharp (programming language)|C#]] programming languages, operations onThe <code>volatile</code> variableskeyword in C and C++ are not [[atomic operation|atomic]]. The <code>volatile</code> keyword has ''never'' functioned as a useful, portable tool for ''any'' multi-threading scenario.<ref>{{cite web |date=21 September 2021 |title=Volatile Keyword In Visual C++ |url=http://msdn2.microsoft.com/en-us/library/12a04hfd.aspx |work=Microsoft MSDN|date=21 September 2021 }}</ref><ref>{{cite web |title=Linux Kernel Documentation – Why the "volatile" type class should not be used |url=https://www.kernel.org/doc/html/latest/process/volatile-considered-harmful.html |work=kernel.org}}</ref><ref>{{cite web |author1=Scott Meyers |author2=Andrei Alexandrescu |year=2004 |title=C++ and the Perils of Double-Checked Locking |url=http://www.aristeia.com/Papers/DDJ_Jul_Aug_2004_revised.pdf |work=DDJ}}</ref><ref>{{cite web |author1=Jeremy Andrews |year=2007 |title=Linux: Volatile Superstition |url=http://kerneltrap.org/Linux/Volatile_Superstition |archive-url=https://web.archive.org/web/20100620121940/http://kerneltrap.org/Linux/Volatile_Superstition |archive-date=2010-06-20 |access-date=Jan 9, 2011 |publisher=kerneltrap.org}}</ref> MostUnlike the [[Java (programming language)|Java]] and [[C Sharp (programming language)|C#]] programming languages, operations on <code>volatile</code> variables in C and C++ compilers,are linkersnot [[atomic operation|atomic]], and runtimesoperations simplyon <code>volatile</code> variables do not providehave thesufficient necessarymemory ordering guarantees (such asi.e. [[memory barrier|memory barriers]]). Most C and C++ compilers, linkers, and runtimes simply do not provide the the necessary memory ordering guarantees to make the <code>volatile</code> keyword useful for ''any'' multi-threading scenario. Before the C11 and C++11 standards, programmers were forced to rely on guarantees from the individual implementations and platforms (e.g. POSIX and WIN32) to write [[thread (computing)|multi-threading]] code. With the modern C11 and C++11 standards, programmers can write portable [[thread (computing)|multi-threading]] code using new portable constructs such as the <code>std::atomic<T></code> templates.<ref>{{cite web |title=volatile (C++) |url=https://msdn.microsoft.com/en-us/library/12a04hfd.aspx |work=Microsoft MSDN|date=21 September 2021 }}</ref>
