Hi, I don't agree with the rationale for excluding a Windows event object-like construct from the Boost thread package. The rationale justifies the exclusion based on the "Concurrent Programming Concepts" paper by Per Brich Hansen in which event variables are dismissed as unsafe. The fundamental problem of event variables according to Hansen's paper is that, "if the sender causes [signals] the event before the receiver waits for it, the receiver will remain delayed until the next event is caused [signalled]". However, Windows event objects don't work like this. From the API specification: "When the state of an auto-reset event object is signaled, it remains signaled until a single waiting thread is released; the system then automatically resets the state to nonsignaled. If no threads are waiting, the event object's state remains signaled." In other words, the receiver will _not_ remain delayed if the sender signals the event before the receiver waits for it. Based on this observation, I think the reference to Hansen's paper should be removed from the rationale. It does not apply to Windows event objects and I had to spend $10 to download the paper from the ACM website and find this out. Furthermore, according to the rationale, "Experienced programmers using the Windows platform today report that event variables are a continuing source of errors". Are there any links to documents that describe these problems? Are these problems perhaps related to the PulseEvent() method, which does cause the behaviour Hansen described but has been deprecated (the API documentation states "This function is unreliable and should not be used. It exists mainly for backward compatibility"). In short, are Windows event objects still considered harmful? Thanks, Robin Boerdijk __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com