= nng_mtx_lock(3supp)
//
// Copyright 2024 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
// copy of which should be located in the distribution where this
// file was obtained (LICENSE.txt).  A copy of the license may also be
// found online at https://opensource.org/licenses/MIT.
//

== NAME

nng_mtx_lock - lock mutex

== SYNOPSIS

[source, c]
----
#include <nng/nng.h>

void nng_mtx_lock(nng_mtx *mtx);
----

== DESCRIPTION

The `nng_mtx_lock()` acquires exclusive ownership of the mutex _mtx_.
If the lock is already owned, this function will wait until the current
owner releases it with xref:nng_mtx_unlock.3supp.adoc[`nng_mtx_unlock()`].

If multiple threads are waiting for the lock, the order of acquisition
is not specified.

NOTE: A mutex can _only_ be unlocked by the thread that locked it.

IMPORTANT: Mutex locks are _not_ recursive; attempts to reacquire the
same mutex may result in deadlock or aborting the current program.
It is a programming error for the owner of a mutex to attempt to
reacquire it.

== RETURN VALUES

None.

== ERRORS

None.

== SEE ALSO

[.text-left]
xref:nng_cv_alloc.3supp.adoc[nng_cv_alloc(3supp)],
xref:nng_mtx_alloc.3supp.adoc[nng_mtx_alloc(3supp)],
xref:nng_mtx_unlock.3supp.adoc[nng_mtx_unlock(3supp)],
xref:nng.7.adoc[nng(7)]