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FDIN(3)			   libdill Library Functions		       FDIN(3)

NAME
       fdin - waits on a file descriptor to become readable

SYNOPSIS
	      #include <libdill.h>

	      int fdin(
		  int fd,
		  int64_t deadline);

DESCRIPTION
       Waits on	a file descriptor (true	OS file	descriptor, not	libdill	socket
       handle)	to  either become readable 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 read	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
        EBADF:	Not a file descriptor.

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

        ECANCELED: Current coroutine was canceled.

        ETIMEDOUT: Deadline was reached.

EXAMPLE
	      int result = fcntl(fd, F_SETFL, O_NONBLOCK);
	      assert(result == 0);
	      while(1) {
		  result = fdin(fd, -1);
		  assert(result	== 0);
		  char buf[1024];
		  ssize_t len =	recv(fd, buf, sizeof(buf), 0);
		  assert(len > 0);
		  process_input(buf, len);
	      }

SEE ALSO
       fdclean(3) fdout(3) now(3)

libdill								       FDIN(3)

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<https://man.freebsd.org/cgi/man.cgi?query=fdin&sektion=3&manpath=FreeBSD+Ports+15.0>

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