threadlocal.tex

\subsection[TLS]{Thread-local storage}

\begin{frame}[fragile]
  \frametitlecpp[20]{Thread-local storage}
  \begin{block}{\cppinline{thread_local} keyword}
    \begin{itemize}
      \item A variable can be declared \cppinline{thread-local}
      \item Then every thread will have its own copy
      \item Most useful for ``working memory'' in each thread
      \item Note: Can also be declared directly on the stack of a thread
      \begin{itemize}
        \item and will be faster, thus should be preferred when possible
      \end{itemize}
    \end{itemize}
  \end{block}
  \begin{exampleblock}{}
    \begin{cppcode*}{}
      thread_local int a{0};
      {
        std::jthread t1([&] { a++; });
        std::jthread t2([&] { a++; });
        a += 2;
      }
      assert( a == 2 ); // Guaranteed to succeed
    \end{cppcode*}
  \end{exampleblock}
\end{frame}