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copied!<p>Slight alternative to Nim's answer:</p> <p>Create</p> <pre><code>class LockedLog { static MutEx mutex; // global mutex for logging ScopedLock lock; // some scoped locker to hold the mutex Logger &oLogger; // reference to the log writer itself public: LockedLog(Logger &oLogger) : oLogger(oLogger), lock(mutex) {} template <typename T> LockedLog &operator<<(const T &value) { oLogger << value; return *this; } }; </code></pre> <p>And either just do:</p> <pre><code>LockedLog(oLogger) << "Log this" << " and this " << " and " << 10 << endl; </code></pre> <p>Or change <code>Logger::operator<<</code> to normal method, call this method in <code>LockedLog::operator<<</code>, add cast-operator to <code>Logger</code>:</p> <pre><code>operator LockedLog() { return LockedLog(*this); } </code></pre> <p>and that should add locking to your current code.</p> <p><strong>Update:</strong> That locks across all the calls to <code>operator<<</code> and <em>may</em> even lock around evaluation of their arguments (depends on whether compiler will evaluate left or right argument first and it may choose). To reduce that, one could:</p> <pre><code>class LockedLog { static MutEx mutex; // global mutex for logging std::stringstream buffer; // temporary formatting buffer; Logger &oLogger; // reference to the log writer itself public: LockedLog(Logger &oLogger) : oLogger(oLogger), lock(mutex) {} template <typename T> LockedLog &operator<<(const T &value) { buffer << value; return *this; } ~LockedLog() { ScopedLock lock(mutex); oLogger << buffer.str() << std::flush; } }; </code></pre> <p>But the <code>stringstream</code> adds another overhead.</p>

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