debian man page for io_wantread

io_wantread(3)						     Library Functions Manual						    io_wantread(3)

NAME
       io_wantread - signal that you want to read from a descriptor

SYNTAX
       #include <io.h>

       void io_wantread(int64 fd);

DESCRIPTION
       io_wantread tells the next io_wait() that you want to read from this descriptor.  Call io_dontwantread() again if you change your mind.

       The  next  time	you  call  io_wait(),  it will look whether this descriptor becomes readable, too.  You can then use io_canread() to check
       whether the descriptor has become readable.

       You have to have called io_fd on the descriptor first (io_pipe and io_socketpair do this for you).  Waiting on descriptors only	works  for
       sockets, fifos and pipes.  It may also work on devices and TTYs, but that is platform dependent -- you should not rely on that.

SEE ALSO
       io_wait(3), io_canread(3), io_wantread(3), io_fd(3)

																    io_wantread(3)