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FDOUT(3)		   libdill Library Functions		      FDOUT(3)

NAME
       fdout - wait on file descriptor to become writable

SYNOPSIS
	      #include <libdill.h>

	      int fdout(
		  int fd,
		  int64_t deadline);

DESCRIPTION
       Waits on	a file descriptor (true	OS file	descriptor, not	libdill	socket
       handle) to either become	writeable or get into an error state.	Either
       case  leads  to	a successful return from the function.	To distinguish
       the two outcomes, follow	up with	a write	operation on the file descrip-
       tor.

       fd: file	descriptor (OS-level one, not a	libdill	handle)

       deadline:  A  point in time when	the operation should time out, in mil-
       liseconds.  Use the now function	to get your current point in time.   0
       means immediate timeout,	i.e., perform the operation if possible	or re-
       turn without blocking if	not.  -1 means no  deadline,  i.e.,  the  call
       will block forever if the operation cannot be performed.

RETURN VALUE
       In case of success the function returns 0.  In case of error it returns
       -1 and sets errno to one	of the values below.

ERRORS
       o EBADF:	Not a file descriptor.

       o EBUSY:	Another	coroutine already blocked on fdout with	this file  de-
	 scriptor.

       o ECANCELED: Current coroutine was canceled.

       o ETIMEDOUT: Deadline was reached.

EXAMPLE
	      int result = fcntl(fd, F_SETFL, O_NONBLOCK);
	      assert(result == 0);
	      while(len) {
		  result = fdout(fd, -1);
		  assert(result	== 0);
		  ssize_t sent = send(fd, buf, len, 0);
		  assert(len > 0);
		  buf += sent;
		  len -= sent;
	      }

SEE ALSO
       fdclean(3) fdin(3) now(3)

libdill								      FDOUT(3)

NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | EXAMPLE | SEE ALSO

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