Thanks, Pablo, I'll have a look at it. James

FYI Matthew Wilson gave a technique (in "Imperfect C++" for handling this, by turning the mutex initialization into an integer initialization (that doesn't have a problem with [multiple] simultaneous threads entering the function)

It uses STLSoft's spin_mutex, and looks pretty much like what you have already:

<code> #include <platformstl/spin_mutex.hpp> #include <stlsoft/lock_scope.hpp> using platformstl::spin_mutex; using stlsoft::lock_scope;

template<typename T> boost::shared_ptr<T> my_func() { // static boost::mutex m; // boost::mutex::scoped_lock l(m); static int spin_count = 0; // No race condition initializing an int spin_mutex mutex(&spin_count); // Build the mutex on top of the static int lock_scope lock(mutex);

static boost::shared_ptr<T> p(new T); return p; } </code>

This assumes, of course, you can (and are willing to) use STLSoft...

HTH, Pablo

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