Here we want the FUNB thread to run, then run Funa, and multi-thread is performed by the time slice polling.
Write the interface of the semaphore, how do we use this semaphore? This requires us to write a multi-thread call function to call.ġ1 // do something 12 cout << " funA " << endl ġ7 this_thread::sleep_for(chrono::seconds( 1 )) ġ8 // do something 19 cout << " funB " << endl For us, these are not much significant, remember these definitions, and define this kind of thing, it is not transferred in our will. Generally, the Wait () function is usually wokener, generally uses a Singal () function, as for the WS operation, but why is the PV operation? Online said is because the human Dicksterra of this system method is defined in Dutch, because in the Dutch Wen, the release of VRIJGEVEN, the PV operation is therefore named. Inside the semaphore, the amount of stuff called PV is used, and the P operation is blocked. So how do we use C ++ to implement a semaphore?ġ0 Semaphore( long count = 0 ) : count(count) ġ1 // V operation, wake up 12 void signal() Second, the implementation of the semaphore The conditions for conditional variables and mutual exclusive, they are the sword you are in the multi-threaded world. Now the signal is also used, so everyone must have a good job. Here I have to mention, the conditional variables and mutex portfolios are really very powerful, the production consumer model is used, and the thread pool is used. So although there is no support amount on the language level in C ++, the same we can use the above two from others. That's right, the implementation of the semaphore is also the condition variable and the mutex lock. See here, I have seen my friends in front of me, I will see this, this is not the usage of the production consumer model mentioned earlier? Some people may be confused, why are you troubled? Are you not going to implement B-line? Then I let the A thread sleep at a little more time? That's right, this idea is ok, but if the B thread is also due to some reasons (such as hardware, operating system reasons), what should I do? How much is the sleeping in the bottom A thread? So the correct approach is to block the B-thread, A thread wakes up this blocking thread.
Simply, for example, I run 2 threads A and B, but I hope that the B thread is executed before the A thread, then we can handle it with a semaphore. To get regular updates on new C programs, you can Follow can discuss these programs on our Facebook Page.Why is the seematic amount? If you search for the answer, many people will tell you that the thread is used for thread communication.
#Implement semaphore p v with pthread c code#
You can easily select the code by double clicking on the code area above. Printf("Philosopher %d is thinkingn",ph_num+1) Printf("Philosopher %d putting fork %d and %d downn",ph_num+1,LEFT+1,ph_num+1) Printf("Philosopher %d is Eatingn",ph_num+1) Printf("Philosopher %d takes fork %d and %dn",ph_num+1,LEFT+1,ph_num+1) If (state = HUNGRY & state != EATING & state != EATING) Printf("Philosopher %d is Hungryn",ph_num+1) Printf("Philosopher %d is thinkingn",i+1) Pthread_create(&thread_id,NULL,philospher,&phil_num) * To find more C programs, do visit * and browse! * You can use all the programs on * for personal and learning purposes. can forever continue to alternate between eating and thinking.
#Implement semaphore p v with pthread c how to#
The problem is how to design a discipline of behavior (a concurrent algorithm) such that each philosopher won’t starve, i.e. These are separate actions: forks must be picked up and put down one by one. Each philosopher can pick up an adjacent fork, when available, and put it down, when holding it.
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