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Diffstat (limited to 'doc/zmq_socket.txt')
| -rw-r--r-- | doc/zmq_socket.txt | 24 |
1 files changed, 17 insertions, 7 deletions
diff --git a/doc/zmq_socket.txt b/doc/zmq_socket.txt index 2156af2..6bcb133 100644 --- a/doc/zmq_socket.txt +++ b/doc/zmq_socket.txt @@ -35,7 +35,7 @@ sockets transfer streams of bytes or discrete datagrams, 0MQ sockets transfer discrete _messages_. 0MQ sockets being _asynchronous_ means that the timings of the physical -connection setup and teardown, reconnect and effective delivery are transparent +connection setup and tear down, reconnect and effective delivery are transparent to the user and organized by 0MQ itself. Further, messages may be _queued_ in the event that a peer is unavailable to receive them. @@ -46,6 +46,18 @@ relationships. With the exception of 'ZMQ_PAIR', 0MQ sockets may be connected incoming connections *from multiple endpoints* bound to the socket using _zmq_bind()_, thus allowing many-to-many relationships. +.Thread safety +A 0MQ 'context' is thread safe and may be shared among as many application +threads as necessary, without any additional locking required on the part of +the caller. + +Individual 0MQ 'sockets' are _not_ thread safe except in the case where full +memory barriers are issued when migrating a socket from one thread to another. +In practice this means applications can create a socket in one thread with +_zmq_socket()_ and then pass it to a _newly created_ thread as part of thread +initialization, for example via a structure passed as an argument to +_pthread_create()_. + .Socket types The following sections present the socket types defined by 0MQ, grouped by the general _messaging pattern_ which is built from related socket types. @@ -100,7 +112,7 @@ Compatible peer sockets:: 'ZMQ_REQ' Direction:: Bidirectional Send/receive pattern:: Receive, Send, Receive, Send, ... Incoming routing strategy:: Fair-queued -Outgoing routing stratagy:: Last peer +Outgoing routing strategy:: Last peer ZMQ_HWM option action:: Drop @@ -166,13 +178,13 @@ ZMQ_HWM option action:: Drop Publish-subscribe pattern ~~~~~~~~~~~~~~~~~~~~~~~~~ The publish-subscribe pattern is used for one-to-many distribution of data from -a single _publisher_ to multiple _subscribers_ in a fanout fashion. +a single _publisher_ to multiple _subscribers_ in a fan out fashion. ZMQ_PUB ^^^^^^^ A socket of type 'ZMQ_PUB' is used by a _publisher_ to distribute data. -Messages sent are distributed in a fanout fashion to all connected peers. +Messages sent are distributed in a fan out fashion to all connected peers. The linkzmq:zmq_recv[3] function is not implemented for this socket type. When a 'ZMQ_PUB' socket enters an exceptional state due to having reached the @@ -186,7 +198,7 @@ Compatible peer sockets:: 'ZMQ_SUB' Direction:: Unidirectional Send/receive pattern:: Send only Incoming routing strategy:: N/A -Outgoing routing strategy:: Fanout +Outgoing routing strategy:: Fan out ZMQ_HWM option action:: Drop @@ -301,8 +313,6 @@ ERRORS ------ *EINVAL*:: The requested socket 'type' is invalid. -*EMTHREAD*:: -The maximum number of sockets within this 'context' has been exceeded. *EFAULT*:: The provided 'context' was not valid (NULL). |