[#BloombergLP-bslmt-RecursiveMutex]
= xref:BloombergLP.adoc[BloombergLP]::xref:BloombergLP/bslmt.adoc[bslmt]::RecursiveMutex
:relfileprefix: ../../
:mrdocs:

This `class` implements a recursive mutex (i.e., a mutex that can be locked any number of times by a thread, and then released by unlocking the mutex the same number of times). If there is an efficient native recursive mutex, this class wraps it. Otherwise, a reasonably efficient proprietary implementation is used. Note that `Mutex` should be preferred if at all possible.

== Synopsis

Declared in `<bslmt_recursivemutex.h>`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
class RecursiveMutex;
----

== Member Functions

[cols="1,4"]
|===
| Name| Description
| xref:BloombergLP/bslmt/RecursiveMutex/2constructor.adoc[`RecursiveMutex`]         [.small]#[constructor]#
| Create a recursive mutex object in the unlocked state. This method does not return normally unless there are sufficient system resources to construct the object.
| xref:BloombergLP/bslmt/RecursiveMutex/2destructor.adoc[`~RecursiveMutex`] [.small]#[destructor]#
| Destroy this recursive mutex object.
| xref:BloombergLP/bslmt/RecursiveMutex/lock.adoc[`lock`] 
| Acquire a lock on this object. If this object is currently locked, then suspend execution of the current thread until a lock can be acquired. Succeed immediately if this thread already holds the lock.
| xref:BloombergLP/bslmt/RecursiveMutex/tryLock.adoc[`tryLock`] 
| Attempt to acquire a lock on this object. Return 0 on success, and a non‐zero value if this object is already locked by another thread, or if an error occurs. Succeed immediately if this thread already holds the lock.
| xref:BloombergLP/bslmt/RecursiveMutex/unlock.adoc[`unlock`] 
| Release a lock on this object that was previously acquired through a call to `lock`, or a successful call to `tryLock`. To fully release the lock, a thread must invoke `unlock` the same number of times it invoked `lock` and `tryLock`. The behavior is undefined unless the calling thread currently owns the lock on this recursive mutex.
|===



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