This class abstracts the Unix system call "poll".
It offers implementations in terms of "poll" itself, "epoll", and "select". (Respectively ifdef'd by RESIP_POLL_IMPL_POLL, RESIP_POLL_IMPL_SELECT, and RESIP_POLL_IMPL_EPOLL.) File descriptors are wrapped by inner class "Poll::FDEntry". The actual "poll" call is represented by method "wait", or if an application wants to control the system call directly, it can instead use methods "beforeExternWait", "setEntryFDStateForExternWait", and "afterExternWait". (The latter are selected by define-ing RESIP_POLL_EXTERN.)
Definition at line 25 of file Poll.hxx.