io_wantwrite - signal that you want to write to a descriptor

       io_wantwrite tells the next io_wait() that you want to write to this descriptor.  Call io_dontwantwrite()
       again if you change your mind.

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

       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.

       io_wantwrite - signal that you want to write to a descriptor

io_wait(3), io_canwrite(3), io_wantwrite(3), io_fd(3)

                                                                                                 io_wantwrite(3)

#include<libowfat/io.h>

       void io_wantwrite(int64 fd);