diff options
Diffstat (limited to 'docs')
| -rw-r--r-- | docs/man/nng_device.3.adoc | 17 |
1 files changed, 12 insertions, 5 deletions
diff --git a/docs/man/nng_device.3.adoc b/docs/man/nng_device.3.adoc index b36d2e80..7151239f 100644 --- a/docs/man/nng_device.3.adoc +++ b/docs/man/nng_device.3.adoc @@ -1,6 +1,6 @@ = nng_device(3) // -// Copyright 2018 Staysail Systems, Inc. <info@staysail.tech> +// Copyright 2021 Staysail Systems, Inc. <info@staysail.tech> // Copyright 2018 Capitar IT Group BV <info@capitar.com> // // This document is supplied under the terms of the MIT License, a @@ -20,14 +20,16 @@ nng_device - message forwarding device #include <nng/nng.h> int nng_device(nng_socket s1, nng_socket s2); + +void nng_device_aio(nng_aio *aio, nng_socket s1, nng_socket s2); ---- == DESCRIPTION -The `nng_device()` function forwards messages received from one +The `nng_device()` and `nng_device_aio()` functions forward messages received from one xref:nng_socket.5.adoc[socket] _s1_ to another socket _s2_, and vice versa. -This function is used to create forwarders, which can be used to create +These functions are used to create forwarders, which can be used to create complex network topologies to provide for improved ((horizontal scalability)), reliability, and isolation. @@ -38,6 +40,8 @@ such as xref:nng_req_open.3.adoc[`nng_req0_open_raw()`]. The `nng_device()` function does not return until one of the sockets is closed. +The `nng_device_aio()` function returns immediately, and operates completely in +the background. === Reflectors @@ -49,7 +53,7 @@ xref:nng_pair.7.adoc[_pair_] or xref:nng_bus.7.adoc[_bus_].) In this case the device acts as a ((reflector)) or loop-back device, where messages received from the valid socket are merely returned -back to the sender. +to the sender. === Forwarders @@ -75,6 +79,9 @@ adjustments to add or remove routing headers as needed. This allows replies to be returned to requesters, and responses to be routed back to surveyors. +The caller of these functions is required to close the sockets when the +device is stopped. + Additionally, some protocols have a maximum ((time-to-live)) to protect against forwarding loops and especially amplification loops. In these cases, the default limit (usually 8), ensures that messages will @@ -88,7 +95,7 @@ IMPORTANT: Not all protocols have support for guarding against forwarding loops, and even for those that do, forwarding loops can be extremely detrimental to network performance. -NOTE: Devices (forwarders and reflectors) act in best effort delivery mode only. +NOTE: Devices (forwarders and reflectors) act in best-effort delivery mode only. If a message is received from one socket that cannot be accepted by the other (due to backpressure or other issues), then the message is discarded. |