= nng_mtx_alloc(3supp)
//
// Copyright 2018 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_alloc - allocate mutex

== SYNOPSIS

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

typedef struct nng_mtx nng_mtx;

int nng_mtx_alloc(nng_mtx **mtxp);
----

== DESCRIPTION

The `nng_mtx_alloc()` function allocates mutex and returns it in _mtxp_.

The mutex objects created by this function are suitable only for
simple lock and unlock operations, and are not recursive.
Every effort has been made to use light-weight underlying primitives when available.

Mutex (mutual exclusion) objects can be thought of as binary semaphores,
where only a single thread of execution is permitted to acquire the semaphore.

Furthermore, a mutex can only be unlocked by the thread that locked it.

== RETURN VALUES

This function returns 0 on success, and non-zero otherwise.

== ERRORS

[horizontal]
`NNG_ENOMEM`:: Insufficient free memory exists.

== SEE ALSO

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