debian man page for io_eagain

io_eagain(3)						     Library Functions Manual						      io_eagain(3)

NAME
       io_eagain - tell io_wait that you got an EAGAIN

SYNTAX
       #include <io.h>

       void io_eagain(int64 fd);

DESCRIPTION
       If  io_wait()  said  that you can read from a descriptor, you try to read from it, and you get EAGAIN, you need to tell io_wait().  This is
       important for edge triggered event notification schemes like Linux 2.4's SIGIO, or you will lose events.

       io_tryread(), io_trywrite() and io_sendfile() and iob_send() already take care of this for you.

       This function is only of interest if you integrate io_wait() with legacy code that uses read/write directly.

SEE ALSO
       io_wait(3)

																      io_eagain(3)