Hi, I've had a good search on the mailing list and while some posts have got close to my problem and given me a few glues, my code does't quite work the way I want it to. My goal is to have a (non-static) class member function run in a child thread + passing a parameter to it. The code I've got at the moment goes something like this: void MyClass::spawn_threads() { for ( int ii = 0; ii < num_threads; ++ii) { threadGroup.create_thread( boost::bind( ChildThreadFunc, _1, ii)); } } void MyClass::ChildThreadFunc( int &threadNumber) { // Does some work } I get the following error on the create_thread line: error: no matching function call to bind(<unknown type>, boost::arg<1>&, int&) cadiates are: .... boost:bind(F, A1, A2)[ with F= void (MyClass::*)(int&), A1=boost:arg<1>, A2=int] I'm confused by the <unknown type> business. How do I tell it the correct type? Maybe someone could point out where I've erred. Cheers, Steve.