filedes

    Points to an array of pollfd structures, one for each file
    descriptor of interest. Each pollfd structure includes the
    following members:

       int fd - The file descriptor
       int events - The requested conditions
       int revents - The reported conditions

 nfds

    The number of pollfd structures in the filedes array.

 timeout

    The maximum length of time (in milliseconds) to wait for at least
    one of the specified events to occur.