85 lines
2.8 KiB
Text
85 lines
2.8 KiB
Text
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= nng_ctx_sendmsg(3)
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//
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// Copyright 2021 Staysail Systems, Inc. <info@staysail.tech>
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//
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// This document is supplied under the terms of the MIT License, a
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// copy of which should be located in the distribution where this
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// file was obtained (LICENSE.txt). A copy of the license may also be
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// found online at https://opensource.org/licenses/MIT.
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//
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== NAME
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nng_ctx_sendmsg - send message using context
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== SYNOPSIS
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[source, c]
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----
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#include <nng/nng.h>
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int nng_ctx_sendmsg(nng_ctx c, nng_msg *msg, int flags);
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----
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== DESCRIPTION
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The `nng_ctx_sendmsg()` sends message _msg_ using the context _ctx_.
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If the function returns zero, indicating it has accepted the message for
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delivery, then the _msg_ is owned by the socket _s_, and the caller
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must not make any further use of it.
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The socket will free the message when it is finished.
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If the function returns non-zero, then it is the caller's responsibility
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to dispose of the _msg_, which may include freeing it, sending it to
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another socket, or simply trying again later.
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NOTE: The semantics of what sending a message means vary from protocol to
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protocol, so examination of the protocol documentation is encouraged.
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The _flags_ may contain the following value:
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`NNG_FLAG_NONBLOCK`::
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The function returns immediately, regardless of whether
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the context is able to accept the data or not.
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If the context is unable to accept the data (such as if backpressure exists
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because the peers are consuming messages too slowly, or no peer is present),
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then the function will return with `NNG_EAGAIN`.
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If this flag is not specified, then the function will block if such a
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condition exists.
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NOTE: Regardless of the presence or absence of `NNG_FLAG_NONBLOCK`, there may
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be queues between the sender and the receiver.
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Furthermore, there is no guarantee that the message has actually been delivered.
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Finally, with some protocols, the semantic is implicitly `NNG_FLAG_NONBLOCK`.
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== RETURN VALUES
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This function returns 0 on success, and non-zero otherwise.
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== ERRORS
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[horizontal]
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`NNG_EAGAIN`:: The operation would block, but `NNG_FLAG_NONBLOCK` was specified.
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`NNG_ECLOSED`:: The context or socket is not open.
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`NNG_EINVAL`:: An invalid set of _flags_ was specified.
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`NNG_EMSGSIZE`:: The value of _size_ is too large.
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`NNG_ENOMEM`:: Insufficient memory is available.
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`NNG_ENOTSUP`:: The protocol does not support sending.
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`NNG_ESTATE`:: The context cannot send data in this state.
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`NNG_ETIMEDOUT`:: The operation timed out.
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== SEE ALSO
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[.text-left]
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xref:nng_msg_alloc.3.adoc[nng_msg_alloc(3)],
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xref:nng_ctx_open.3.adoc[nng_ctx_open(3)],
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xref:nng_ctx_recvmsg.3.adoc[nng_ctx_recvmsg(3)],
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xref:nng_ctx_send.3.adoc[nng_ctx_send(3)],
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xref:nng_sendmsg.3.adoc[nng_sendmsg(3)],
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xref:nng_strerror.3.adoc[nng_strerror(3)],
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xref:nng_msg.5.adoc[nng_msg(5)],
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xref:nng_ctx.5.adoc[nng_ctx(5)],
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xref:nng.7.adoc[nng(7)]
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