[boost] [threads] rw_lock question

Hello, I was looking at rw_lock implementation in the thread_dev branch and see that member variable m_num_waiting_promotion is only set in constructor to '0' and then once tested for equality with 1. So, looks like it has no effect at all? Did I miss anything? Note: I'm not yet planning to use rw_lock, I'm just looking at implementation. - Volodya