Kevin Martin wrote:
On 8 May 2008, at 04:09, Peisheng Wang wrote:
You are importing the namespace boost, so mutex is both a variable name and a type name, the compiler gets confused.
...
boost::mutex mutex;
void increment_count() { boost::mutex::scoped_lock lock(mutex);
Yes. Specifically, the line above could be interpreted as the declaration of a function lock() accepting an unnamed mutex by value and returning a boost::mutex::scoped_lock (the "most vexing parse"). Kevin's suggestion is probably best to keep things straight for the reader as well as for the compiler. It might also work to use assignment-style initialization? I haven't tried it for this case. boost::mutex::scoped_lock lock = mutex; I mention that more as a tactic for future function-vs.-object declaration ambiguities than for this particular one.