io: make io_close_taken_fd() unset nonblocking on the fd.

[ccan] / ccan / io / io.h

diff --git a/ccan/io/io.h b/ccan/io/io.h
index c1d09963caa9a813bb9560763e1fd07269b8c97f..1664df65f26e353120762f1ab89abc65ee01f1c9 100644 (file)
--- a/ccan/io/io.h
+++ b/ccan/io/io.h
@@ -109,7 +109,8 @@ void io_set_finish_(struct io_conn *conn,
  * @arg: the argument to @init.
  *
  * When @fd becomes readable, we accept(), create a new connection,
- * (tal'ocated off @ctx) and pass that to init().
+ * (tal'ocated off @ctx) and pass that to init().  Note that if there is
+ * an error on this file descriptor, it will be freed.
  *
  * Returns NULL on error (and sets errno).
  *
@@ -627,6 +628,26 @@ struct io_plan *io_close(struct io_conn *conn);
  */
 struct io_plan *io_close_cb(struct io_conn *, void *unused);
 
+/**
+ * io_close_taken_fd - close a connection, but remove the filedescriptor first.
+ * @conn: the connection to take the file descriptor from and close.
+ *
+ * io_close closes the file descriptor underlying the io_conn; this version does
+ * not.  Presumably you have used io_conn_fd() on it beforehand and will take
+ * care of the fd yourself.
+ *
+ * Note that this also turns off O_NONBLOCK on the fd.
+ *
+ * Example:
+ * static struct io_plan *steal_fd(struct io_conn *conn, int *fd)
+ * {
+ *     *fd = io_conn_fd(conn);
+ *     printf("stealing fd %i and closing\n", *fd);
+ *     return io_close_taken_fd(conn);
+ * }
+ */
+struct io_plan *io_close_taken_fd(struct io_conn *conn);
+
 /**
  * io_loop - process fds until all closed on io_break.
  * @timers - timers which are waiting to go off (or NULL for none)
@@ -645,7 +666,10 @@ void *io_loop(struct timers *timers, struct timer **expired);
  * io_conn_fd - get the fd from a connection.
  * @conn: the connection.
  *
- * Sometimes useful, eg for getsockname().
+ * Sometimes useful, eg for getsockname().  Note that the fd is O_NONBLOCK.
+ *
+ * See Also:
+ *     io_close_taken_fd
  */
 int io_conn_fd(const struct io_conn *conn);