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| Member functions | ||||
| Locking | ||||
mutex::try_lock | ||||
| Native handle | ||||
bool try_lock(); | (since C++11) | |
Tries to lock the mutex. Returns immediately. On successful lock acquisition returnstrue, otherwise returnsfalse.
This function is allowed to fail spuriously and returnfalse even if the mutex is not currently locked by any other thread.
Iftry_lock is called by a thread that already owns themutex, the behavior is undefined.
Priorunlock() operation on the same mutexsynchronizes-with (as defined instd::memory_order) this operation if it returnstrue. Note that priorlock() does not synchronize with this operation if it returnsfalse.
Contents |
(none)
true if the lock was acquired successfully, otherwisefalse.
Throws nothing.
#include <chrono>#include <iostream> // std::cout#include <mutex>#include <thread> std::chrono::milliseconds interval(100); std::mutex mutex;int job_shared=0;// both threads can modify 'job_shared',// mutex will protect this variable int job_exclusive=0;// only one thread can modify 'job_exclusive'// no protection needed // this thread can modify both 'job_shared' and 'job_exclusive'void job_1(){std::this_thread::sleep_for(interval);// let 'job_2' take a lock while(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'void job_2(){ mutex.lock();std::this_thread::sleep_for(5* interval);++job_shared; mutex.unlock();} int main(){std::thread thread_1(job_1);std::thread thread_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)
| locks the mutex, blocks if the mutex is not available (public member function)[edit] | |
| unlocks the mutex (public member function)[edit] | |
C documentation formtx_trylock | |
