File locked_condition_variable.hpp¶

namespace shared_memory

All templated types in this namespaces are elementary types: int, double, float, char*, …

Typedefs

typedef boost::interprocess::interprocess_mutex UnamedSHMMutex¶

typedef boost::interprocess::interprocess_condition UnamedSHMCondition¶

typedef boost::interprocess::scoped_lock<UnamedSHMMutex> UnamedSHMLock¶

class LockedConditionVariable

#include <locked_condition_variable.hpp>

The LockedConditionVariable class is here as a anonymous layer on top of the boost intersprocess condition variable labrary.

It creates a condition variable in a shared memory automatically.

Public Functions

LockedConditionVariable(const std::string object_id, bool clean_memory_on_destruction = true)

A condition variable shared over the memory The condition variable is cleaned from the memory on destruction if clean_memory_on_destruction is set to true.

Contrary to shared_memory::ConditionVariable, instances of this class manages their mutex and lock internally, with the consequence the mutex can be locked and unlocked exclusively through other instances of LockedConditionVariable.

~LockedConditionVariable()

void notify_all(): notify_all is notifying all condition variables with the same mutex

void notify_one(): notify_one notifies one condition variable with the same mutex

void wait(): wait waits until another thread notifies this object

bool timed_wait(long wait_nano_seconds)

timed_wait wait a notify during a certain certain time and then wake up

Parameters:: wait_duration – in microsecond
Returns:: true: the condition variable has been notified, false otherwize

bool try_lock()

try_lock Tries to acquire the lock without waiting.

Throws :
Returns:: true if manages to acquire the lock, false otherwise.

void unlock()

unlock Unlocks the lock.

Throws :

bool owns()

void lock_scope()

lock_scope this function is used to lock the part of the code that needs protection.

It locks the mutex until unlock_scope is used

void unlock_scope(): unlock_scope this function unlock the mutex so remove the protection of the code

Public Members

SHMMutex mutex_: mutex_ is the mutex associated to the condition variable

SHMCondition *condition_variable_: condition_variable_ is the boost condition variable that is used

std::unique_ptr<SHMScopeLock> lock_: lock_ is a object that protects the codes with a mutex, see the boost documentation about “boost::interprocess::scoped_lock”

bool clean_memory_on_destruction_: if true (the default), clean the shared memory of the hosted mutex and condition.

Public Static Functions

static void clean(const std::string segment_id)

LockedConditionVariable clean their shared memory on destruction.

But the destructor may have failed to be called if for some reason the program crashed.

Private Members

std::string mutex_id_: mutex_id_ is the mutex name in the shared memory

std::string condition_id_: condition_id_ is the condition variable name in the shared memory

boost::interprocess::managed_shared_memory segment_manager_: shm_segment is the boost object that manages the shared memory segment