PTHREAD_RWLOCK_PREFER_WRITER_NP, //很唬人, 但是也是读者优先 PTHREAD_RWLOCK_PREFER_WRITER_NONRECURSIVE_NP, //写者优先 PTHREAD_RWLOCK_DEFAULT_NP = PTHREAD_RWLOCK_PREFER_READER_NP 读者优先:读锁来请求可以立即响应,只要有一个读锁没完成,那么写锁就无法写。这种策略是不公平的,极端情况下,写现场很可能...
还好,Linux有pthread_rwlockattr_setkind_np这个函数。 enum { PTHREAD_RWLOCK_PREFER_READER_NP, PTHREAD_RWLOCK_PREFER_WRITER_NP, PTHREAD_RWLOCK_PREFER_WRITER_NONRECURSIVE_NP, PTHREAD_RWLOCK_DEFAULT_NP =PTHREAD_RWLOCK_PREFER_READER_NP }; 可是直接pthread_rwlockattr_setkind_np(&attr,PTHREAD_RWLOCK_PREFER...
PTHREAD_RWLOCK_PREFER_WRITER_NP,//读者优先 PTHREAD_RWLOCK_PREFER_WRITER_NONRECURSIVE_NP,//写者优先 PTHREAD_RWLOCK_DEFAULT_NP = PTHREAD_RWLOCK_PREFER_READER_NP//读者优先 }; 1 /* 获取与设置属性 */intpthread_rwlockattr_getkind_np(constpthread_rwlockattr_t * attr,int* pref);intpthread_rwlocka...
PTHREAD_RWLOCK_PREFER_READER_NP,//读者优先(默认属性)PTHREAD_RWLOCK_PREFER_WRITER_NP,//读者优先PTHREAD_RWLOCK_PREFER_WRITER_NONRECURSIVE_NP,//写者优先PTHREAD_RWLOCK_DEFAULT_NP = PTHREAD_RWLOCK_PREFER_READER_NP//读者优先}; staticboolrwlock_attr_initialized =false;staticpthread_rwlockattr_t rwlock_at...
A subroutinepthread_rwlock_attr_getfavorwriters_npretorna a preferência atual que é definida na estrutura de atributos de bloqueio de leitura / gravação. Por padrão, o leitor-threads são preferidos sobre o writer-threads para obter um bloqueio de leitura / grava...
PTHREAD_RWLOCK_PREFER_WRITER_NONRECURSIVE_NP, PTHREAD_RWLOCK_DEFAULT_NP = PTHREAD_RWLOCK_PREFER_READER_NP }; 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 总的来说,这样的锁建立之后一定要设置优先级,不然就容易出现写线程饥饿。而且读写锁适合读多写少的情况,如果读、写一样多,那这时候还是用mute...
为了控制写线程饥饿,必须要在创建读写锁的时候设置PTHREAD_RWLOCK_PREFER_WRITER_NONRECURSIVE,不要用PTHREAD_RWLOCK_PREFER_WRITER_NP啊,这个似乎没什么用,感觉应该是个bug,不要问我是怎么知道的。。。 /// /usr/include/pthread.h /* Read-write lock types. */ #if defined...
PTHREAD_MUTEX_ERRORCHECK_NP, PTHREAD_MUTEX_ADAPTIVE_NP #ifdef __USE_UNIX98 , PTHREAD_MUTEX_NORMAL = PTHREAD_MUTEX_TIMED_NP, PTHREAD_MUTEX_RECURSIVE = PTHREAD_MUTEX_RECURSIVE_NP, PTHREAD_MUTEX_ERRORCHECK = PTHREAD_MUTEX_ERRORCHECK_NP,
pthread_rwlockattr_setkind_np(&attr,PTHREAD_RWLOCK_PREFER_WRITER_NP); if(pthread_rwlock_init(&rwlock,&attr)){ printf("Could not create a rwlock\n"); return-1; } intthreadCount[]={1,2,3}; if(pthread_create(&thr1, NULL, &thr1_entry, (void*)&threadCount[0])) { printf("Could ...
pthread的各种同步机制 pthread的各种同步机制 简述 pthread是POSIX标准的多线程库，UNIX、Linux上广泛使用，windows上也有对应的实现，所有的函数都是pthread打头，也就一百多个函数，不是很复杂。然而多线程编程被普遍认为复杂，主要是因为多线程给程序引入了一定的不可预知性，要控制这些不可预知性，就需要使用各种锁...