What I do is having operator bool () return true if the coroutine has not terminated and has data.
How does this indicate that the next call to coroutine<>::operator() would not return a value?
Also, the coroutine-fn is called immediately when the coroutine is called, and not deferred to the first operator() call.
I don't get it - when will be the body of coroutine-fn entered? coro_t c( fn);//? or c(); //? In the current implementation the first call of coroutine<>::operator() enters the body of the coroutine-fn. example with some additional arguments: typedef coroutine< std::string(int) > coro1_t; typedef coroutine< int(std::string) > coro2_t; void fn( coro2_t & c){ int x = c.get(); c( textual_cast( x) ); x = c.get(); c( textual_cast( x) ); } coro1_t c( fn); c( 1); // fn() is entered here std::string str = c.get(); int i = 0; for(; c ; c( ++i)) { std::string s = c.get(); } I think your forr-loop would not work . After the second call to 'c( i++)' in the loop 'c.get()' returns a value ('two'). 'coroutine::operator bool()' will evaluate to true (because result is available). If the next time c( ++i) is called the code returns from the last 'c( textual_cast( x) );' in coroutine-fn and terminates fn() - no data is returned. Because the for-loop does not test 'coroutine::operator bool()' before 'c.get()' you get a fault. Oliver