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io_fd_canwrite(3)	   Library Functions Manual	     io_fd_canwrite(3)

NAME
       io_fd_canwrite -	prepare	descriptor for io_wait

SYNTAX
       #include	<libowfat/io.h>

       int io_fd(int64 fd); int	io_fd_canwrite(int64 fd);

DESCRIPTION
       io_fd_canwrite  is just like io_fd, except that it assumes the descrip-
       tor is writable,	which may save a syscall or two.  This	assumption  is
       true  in	 most  cases,  because	the kernel buffers writes.  Noteworthy
       cases in	which you need to use io_fd instead of io_fd_canwrite are  un-
       connected  sockets,  i.e.  when you queued a non-blocking connect() and
       want to ask for writability to get notified when	it went	through.

       It is OK	to call	this function on a descriptor that io_fd() has already
       been called on.

RETURN VALUE
       io_fd_canwrite returns 1	on success, 0 on error.

SEE ALSO
       io_wait(3),  io_wantread(3),   io_canread(3),   io_eagain(3),   io_non-
       block(3), io_fd(3)

							     io_fd_canwrite(3)

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