std::recursive_mutex::try_lock

 

C++

Language

Concepts

Utilities library

Strings library

Containers library

Algorithms library

Iterators library

Numerics library

Input/output library

Localizations library

Regular expressions library (C++11)

Atomic operations library (C++11)

Thread support library (C++11)

 

Thread support library

Threads
thread (C++11)
this_thread namespace
get_id (C++11) yield (C++11)	sleep_for (C++11) sleep_until (C++11)
Mutual exclusion
mutex (C++11) timed_mutex (C++11)	recursive_mutex (C++11) recursive_timed_mutex (C++11)
Generic lock management
lock_guard (C++11) unique_lock (C++11) defer_lock_t try_to_lock_t adopt_lock_t (C++11) (C++11) (C++11)	lock (C++11) try_lock (C++11) defer_lock try_to_lock adopt_lock (C++11) (C++11) (C++11)
Condition variables
condition_variable (C++11)
condition_variable_any (C++11)
notify_all_at_thread_exit (C++11)
cv_status (C++11)
Futures
promise (C++11) future (C++11) shared_future (C++11) packaged_task (C++11) async (C++11)	launch (C++11) future_status (C++11) future_error (C++11) future_category (C++11) future_errc (C++11)

 

std::recursive_mutex

Member functions

recursive_mutex::recursive_mutex

Locking

recursive_mutex::lock

recursive_mutex::try_lock

recursive_mutex::unlock

Native handle

recursive_mutex::native_handle

 

bool try_lock();		(since C++11)

Tries to lock the mutex. Returns immediately. On successful lock acquisition returns true, otherwise returns false.

Parameters

(none)

Return value

true if the lock was acquired successfully, otherwise false.

Example

This example shows lock, try_lock and unlock in action

#include <iostream>
#include <mutex>
 
int main()
{
    std::mutex test;
    if (test.try_lock()==true)
        std::cout << "lock acquired" << std::endl;
    else
        std::cout << "lock not acquired" << std::endl;
    test.unlock();	//now unlock the mutex
    test.lock();	//to lock it again
    if (test.try_lock())  //true can be left out
        std::cout << "lock acquired" << std::endl;
    else
        std::cout << "lock not acquired" << std::endl;
    test.lock(); //and now the finale (a block)
}

Output:

lock acquired
lock not acquired
(program hangs)

See also

lock	locks the mutex, blocks if the mutex is not available (public member function)
unlock	unlocks the mutex (public member function)