From cppreference.com
booltry_lock();(since C++11)Tries to lock the mutex. Returns immediately. On successful lock acquisition returns true, otherwise returns false.
This function is allowed to fail spuriously and return false even if the mutex is not currently locked by any other thread.
If try_lock is called by a thread that already owns the mutex, the behavior is undefined.
Prior
operation on the same mutex synchronizes-with (as defined in
) this operation if it returns true. Note that prior
does not synchronize with this operation if it returns false.
Parameters
(none)
Return value
true if the lock was acquired successfully, otherwise false.
Exceptions
Throws nothing.
Example
Run this code
#include<chrono>#include<iostream> // std::cout#include<mutex>#include<thread>std::chrono::millisecondsinterval(100);std::mutexmutex;intjob_shared=0;// both threads can modify 'job_shared',// mutex will protect this variableintjob_exclusive=0;// only one thread can modify 'job_exclusive'// no protection needed// this thread can modify both 'job_shared' and 'job_exclusive'voidjob_1(){std::this_thread::sleep_for(interval);// let 'job_2' take a lockwhile(true){// try to lock mutex to modify 'job_shared'if(mutex.try_lock()){std::cout<<"job shared ("<<job_shared<<")\n";mutex.unlock();return;}else{// can't get lock to modify 'job_shared'// but there is some other work to do++job_exclusive;std::cout<<"job exclusive ("<<job_exclusive<<")\n";std::this_thread::sleep_for(interval);}}}// this thread can modify only 'job_shared'voidjob_2(){mutex.lock();std::this_thread::sleep_for(5*interval);++job_shared;mutex.unlock();}intmain(){std::threadthread_1(job_1);std::threadthread_2(job_2);thread_1.join();thread_2.join();}Possible output:
job exclusive (1) job exclusive (2) job exclusive (3) job exclusive (4) job shared (1) See also