标签:pthread mutex cond pthread_cond_wait 条件变量
情景1:
Jack开着一辆出租车来到一个站点停车,看见没人就走了。过段时间,Susan来到站点准备乘车,但是没有来,于是就等着。过了一会Mike开着车来到了这个站点,Sunsan就上了Mike的车走了。如图所示:
程序实现该情景:
#include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <pthread.h> pthread_cond_t taxicond = PTHREAD_COND_INITIALIZER; pthread_mutex_t taximutex = PTHREAD_MUTEX_INITIALIZER; void *traveler_arrive(void *name) { char *p = (char *)name; printf ("Travelr: %s need a taxi now!\n", p); pthread_mutex_lock(&taximutex); pthread_cond_wait(&taxicond, &taximutex); pthread_mutex_unlock(&taximutex); printf ("traveler: %s now got a taxi!\n", p); pthread_exit(NULL); } void *taxi_arrive(void *name) { char *p = (char *)name; printf ("Taxi: %s arrives.\n", p); pthread_cond_signal(&taxicond); pthread_exit(NULL); } int main (int argc, char **argv) { char *name; pthread_t thread; pthread_attr_t threadattr; pthread_attr_init(&threadattr); name = "Jack"; pthread_create(&thread, &threadattr, taxi_arrive, name); sleep(1); name = "Susan"; pthread_create(&thread, &threadattr, traveler_arrive, name); sleep(1); name = "Mike"; pthread_create(&thread, &threadattr, taxi_arrive, name); sleep(1); return 0; } /* ----- End of main() ----- */
Jack开着一辆出租车来到一个站点停车,看见没人就等着。过段时间,Susan来到站点准备乘车看见了Jack的出租车,于是就上去了。过了一会Mike开着车来到了这个站点,看见没人救等着。如图所示:
程序实现该情景:
#include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <pthread.h> int travelercount = 0; pthread_cond_t taxicond = PTHREAD_COND_INITIALIZER; pthread_mutex_t taximutex = PTHREAD_MUTEX_INITIALIZER; void *traveler_arrive(void *name) { char *p = (char *)name; pthread_mutex_lock(&taximutex); printf ("traveler: %s need a taxi now!\n", p); travelercount++; pthread_cond_wait(&taxicond, &taximutex); pthread_mutex_unlock(&taximutex); printf ("traveler: %s now got a taxi!\n", p); pthread_exit(NULL); } void *taxi_arrive(void *name) { char *p = (char *)name; printf ("Taxi: %s arrives.\n", p); for(;;){ if(travelercount){ pthread_cond_signal(&taxicond); travelercount--; break; } } pthread_exit(NULL); } int main (int argc, char **argv) { char *name; pthread_t thread; pthread_attr_t threadattr; pthread_attr_init(&threadattr); name = "Jack"; pthread_create(&thread, &threadattr, taxi_arrive, name); sleep(1); name = "Susan"; pthread_create(&thread, &threadattr, traveler_arrive, name); sleep(3); name = "Mike"; pthread_create(&thread, &threadattr, taxi_arrive, name); sleep(4); return 0; } /* ----- End of main() ----- */
author: fulinux
E-mail: fulinux@sina.com
blog: blog.csdn.net/fulinus
标签:pthread mutex cond pthread_cond_wait 条件变量
原文地址:http://blog.csdn.net/fulinus/article/details/39342371