oxmox
17f68cf8fe
git-subtree-dir: external/nng git-subtree-split: 169221da8d53b2ca4fda76f894bee8505887a7c6
63 lines
1.9 KiB
Text
63 lines
1.9 KiB
Text
= nng_msg_reserve(3)
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//
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// Copyright 2018 Staysail Systems, Inc. <info@staysail.tech>
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// Copyright 2018 Capitar IT Group BV <info@capitar.com>
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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_msg_reserve - reserve storage for a message
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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_msg_reserve(nng_msg *msg, size_t capacity);
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----
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== DESCRIPTION
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The `nng_msg_reserve()` function ensures a message has allocated enough storage
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to accommodate a body of the given length.
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This message attempts to avoid extra allocations,
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and will reuse the existing memory when possible.
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TIP: Using this message before xref:nng_msg_append.3.adoc[`nng_msg_append()`]
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will prevent additional memory allocations until the message's length exceeds
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the alotted capacity.
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NOTE: Pointers to message body and header content obtained prior to this
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function must not be in use, as the underlying memory used for the message
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may have changed, particularly if the message capacity is increasing.
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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_ENOMEM`:: Insufficient free memory exists to reallocate a message.
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== SEE ALSO
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[.text-left]
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xref:nng_msg_capacity.3.adoc[nng_msg_capacity(3)],
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xref:nng_msg_alloc.3.adoc[nng_msg_alloc(3)],
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xref:nng_msg_append.3.adoc[nng_msg_append(3)],
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xref:nng_msg_body.3.adoc[nng_msg_body(3)],
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xref:nng_msg_chop.3.adoc[nng_msg_chop(3)],
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xref:nng_msg_free.3.adoc[nng_msg_free(3)],
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xref:nng_msg_insert.3.adoc[nng_msg_insert(3)],
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xref:nng_msg_len.3.adoc[nng_msg_len(3)],
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xref:nng_msg_trim.3.adoc[nng_msg_trim(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.7.adoc[nng(7)]
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