doc updates

doc/manual/parallel-computing.rst

@@ -452,12 +452,14 @@ holding objects of type ``T``. Multiple readers can read off the channel
 via ``fetch`` and ``take!``. Multiple writers can add to the channel via
 ``put!``. ``isready`` tests for the prescence of any object in
 the channel, while ``wait`` waits for an object to become available.
+``close`` closes a Channel. On a closed channel, ``put!`` will fail,
+while ``take!`` and ``fetch`` successfully return any existing values
+till it is emptied.
 
 A Channel can be used as an iterable object in a ``for`` loop, in which
-case the loop runs till the channel is open. The loop variable takes on
-all values added to the channel. ``close`` closes a Channel causing
-the loop to terminate.
-
+case the loop runs as long as the channel has data or is open. The loop
+variable takes on all values added to the channel. An empty, closed channel
+causes the ``for`` loop to terminate.
 
 
 Shared Arrays (Experimental)

doc/stdlib/parallel.rst

@@ -303,6 +303,14 @@ General Parallel Computing Support
        @async put!(rr, remotecall_fetch(p, long_computation))
        isready(rr)  # will not block
 
+.. function:: close(Channel)
+
+    Closes a channel. An exception is thrown by:
+
+    * ``put!`` on a on a closed channel.
+
+    * ``take!`` and ``fetch`` on an empty, closed channel.
+
 .. function:: RemoteRef()
 
    Make an uninitialized remote reference on the local machine.