pmem::obj::mutex Class Reference

Persistent memory resident mutex implementation. More...

#include <libpmemobj++/mutex.hpp>

Public Types
typedef PMEMmutex *	native_handle_type
	Implementation defined handle to the native type.

Public Member Functions
	mutex ()
	Default constructor. More...
	~mutex ()=default
	Defaulted destructor.
void	lock ()
	Locks the mutex, blocks if already locked. More...
bool	try_lock ()
	Tries to lock the mutex, returns regardless if the lock succeeds. More...
void	unlock ()
	Unlocks a previously locked mutex. More...
native_handle_type	native_handle () noexcept
	Access a native handle to this condition variable. More...
enum pobj_tx_param	lock_type () const noexcept
	The type of lock needed for the transaction API. More...
mutex &	operator= (const mutex &)=delete
	Deleted assignment operator.
	mutex (const mutex &)=delete
	Deleted copy constructor.

Private Attributes
PMEMmutex	plock
	A POSIX style PMEM-resident mutex.

Detailed Description

Persistent memory resident mutex implementation.

This class is an implementation of a PMEM-resident mutex which mimics in behavior the C++11 std::mutex. This class satisfies all requirements of the Mutex and StandardLayoutType concepts. The typical usage example would be:

#include <libpmemobj++/mutex.hpp>
#include <libpmemobj++/persistent_ptr.hpp>
#include <libpmemobj++/pool.hpp>
#include <mutex>
 
namespace nvobj = pmem::obj;
 
void
unique_guard_example()
{
    // pool root structure
    struct root {
        nvobj::mutex pmutex;
    };
 
    // create a pmemobj pool
    auto pop = nvobj::pool<root>::create("poolfile", "layout",
                         PMEMOBJ_MIN_POOL);
    auto proot = pop.root();
 
    // typical usage schemes
    std::lock_guard<nvobj::mutex> guard(proot->pmutex);
 
    std::unique_lock<nvobj::mutex> other_guard(proot->pmutex);
}

Constructor & Destructor Documentation

mutex()

pmem::obj::mutex::mutex ( )

inline

Default constructor.

Exceptions

lock_error

when the mutex is not from persistent memory.

Member Function Documentation

lock()

void pmem::obj::mutex::lock ( )

inline

Locks the mutex, blocks if already locked.

If a different thread already locked this mutex, the calling thread will block. If the same thread tries to lock a mutex it already owns, the behavior is undefined.

Exceptions

lock_error

when an error occurs, this includes all system related errors with the underlying implementation of the mutex.

lock_type()

enum pobj_tx_param pmem::obj::mutex::lock_type ( ) const

inlinenoexcept

The type of lock needed for the transaction API.

Returns

TX_PARAM_MUTEX

native_handle()

native_handle_type pmem::obj::mutex::native_handle ( )

inlinenoexcept

Access a native handle to this condition variable.

Returns

a pointer to PMEMmutex.

try_lock()

bool pmem::obj::mutex::try_lock ( )

inline

Tries to lock the mutex, returns regardless if the lock succeeds.

If the same thread tries to lock a mutex it already owns, the behavior is undefined.

Returns

true on successful lock acquisition, false otherwise.

Exceptions

lock_error

when an error occurs, this includes all system related errors with the underlying implementation of the mutex.

unlock()

void pmem::obj::mutex::unlock ( )

inline

Unlocks a previously locked mutex.

Unlocking a mutex that has not been locked by the current thread results in undefined behavior. Unlocking a mutex that has not been lock also results in undefined behavior.

---

The documentation for this class was generated from the following file:

• libpmemobj++/mutex.hpp