66 lines
1.7 KiB
Text
66 lines
1.7 KiB
Text
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= nng_mtx_lock(3supp)
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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_mtx_lock - lock mutex
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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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#include <nng/supplemental/util/platform.h>
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void nng_mtx_lock(nng_mtx *mtx);
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----
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== DESCRIPTION
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The `nng_mtx_lock()` acquires exclusive ownership of the mutex _mtx_.
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If the lock is already owned, this function will wait until the current
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owner releases it with xref:nng_mtx_unlock.3supp.adoc[`nng_mtx_unlock()`].
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If multiple threads are waiting for the lock, the order of acquisition
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is not specified.
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NOTE: A mutex can _only_ be unlocked by the thread that locked it.
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IMPORTANT: Mutex locks are _not_ recursive; attempts to reacquire the
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same mutex may result in deadlock or aborting the current program.
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It is a programming error for the owner of a mutex to attempt to
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reacquire it.
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****
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_NNG_ offers neither a non-blocking variant that can fail,
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nor recursive mutexes.
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This is by design, as _NNG_ itself does not use such things,
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and most often the need for them is the result of poor design.
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If such capabilities are needed, they may be synthesized fairly
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easily from mutexes and condition variables.
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****
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== RETURN VALUES
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None.
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== ERRORS
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None.
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== SEE ALSO
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[.text-left]
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xref:nng_cv_alloc.3supp.adoc[nng_cv_alloc(3supp)],
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xref:nng_mtx_alloc.3supp.adoc[nng_mtx_alloc(3supp)],
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xref:nng_mtx_unlock.3supp.adoc[nng_mtx_unlock(3supp)],
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xref:nng.7.adoc[nng(7)]
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