module Netsys_pollset_posix:sig..end
Pollsets for POSIX operating systems
val poll_based_pollset : unit -> Netsys_pollset.pollsetReturns a poll set whose implementation is based on the poll system
      call.
Win32: On Win32 this implementation works, but only for sockets,
      and is not cancellable in multi-threaded programs. (This is a 
      restriction because we have to map it to the select call of the
      WinSock layer.)
val reset : unit -> unitThis module may keep some global state. This function resets this
      state. As the state may contain file descriptors, it is advisable
      to reset after calling fork to free these descriptors.
val accelerated_pollset : unit -> Netsys_pollset.pollsetReturns a pollset using a "fast" poll mechanism, if available.
      Otherwise this is the same as poll_based_pollset.
Fast poll mechanisms are:
epoll on LinuxGenerally, these mechanisms are not 100% compatible with the
      standard poll. In particular, the poll events may be slightly
      differently interpreted. Also, there are many, many reports about
      buggy implementations in the OS.