VMS Help CC, Socket Routines, select  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    Allows you to poll or check a group of sockets for I/O
    activity. It can check what sockets are ready to be read or
    written, or what sockets have a pending exception.

    Syntax:

      #include <time.h>

    _DECC_V4_SOURCE defined:

       int select(int nfds, int *readfds, int *writefds,
                   int *exceptfds, struct timeval *timeout);

    _DECC_V4_SOURCE not defined:

       int select(int nfds, fd_set *readfds, fd_set *writefds,
                   fd_set *exceptfds, struct timeval *timeout);