UsingAout.tex

\section{Using \texttt{aout} -- A Concurrency-safe Wrapper for \texttt{cout}}

When using \lstinline^cout^ from multiple actors, output often appears interleaved.
Moreover, using \lstinline^cout^ from multiple actors -- and thus from multiple threads -- in parallel should be avoided regardless, since the standard does not guarantee a thread-safe implementation.

By replacing \texttt{std::cout} with \texttt{caf::aout}, actors can achieve a concurrency-safe text output.
The header \lstinline^caf/all.hpp^ also defines overloads for \texttt{std::endl} and \texttt{std::flush} for \lstinline^aout^, but does not support the full range of ostream operations (yet).
Each write operation to \texttt{aout} sends a message to a `hidden' actor.
This actor only prints lines, unless output is forced using \lstinline^flush^.
The example below illustrates printing of lines of text from multiple actors (in random order).

\lstinputlisting{../examples/aout.cpp}