pthread_cond_signal如何才能保证不被丢失 - Chinaunix

#include <unistd.h>
#include <pthread.h>
#include <ostream>
#include <iostream>
using namespace std ;
void* routine1(void* p) ;
void* routine2(void* p) ;
void* routine3(void* p) ;
int flag = 1 ;
pthread_mutex_t mux ;
//static pthread_mutexattr_t muxattr = PTHREAD_MUTEX_TIMED_NP ;
static pthread_cond_t cond1 = PTHREAD_COND_INITIALIZER ;
static pthread_cond_t cond2 = PTHREAD_COND_INITIALIZER ;
static pthread_cond_t cond3 = PTHREAD_COND_INITIALIZER ;
int main(int argc, char* argv[])
{
pthread_t id1, id2, id3 ;
pthread_attr_t attr1, attr2, attr3 ;
pthread_cond_init(&cond1, NULL) ;
pthread_cond_init(&cond2, NULL) ;
pthread_cond_init(&cond3, NULL) ;
pthread_mutex_init(&mux, 0) ;
pthread_attr_init(&attr1) ;
pthread_attr_init(&attr2) ;
pthread_attr_init(&attr3) ;
pthread_attr_setdetachstate(&attr1, PTHREAD_CREATE_JOINABLE) ;
pthread_attr_setdetachstate(&attr2, PTHREAD_CREATE_JOINABLE) ;
pthread_attr_setdetachstate(&attr3, PTHREAD_CREATE_JOINABLE) ;
pthread_attr_setstacksize(&attr1, 1024*100) ;
pthread_attr_setstacksize(&attr2, 1024*100) ;
pthread_attr_setstacksize(&attr3, 1024*100) ;
pthread_create(&id1, &attr1, routine1, (void*)NULL) ;
pthread_create(&id2, &attr2, routine2, (void*)NULL) ;
pthread_create(&id3, &attr3, routine3, (void*)NULL) ;
sleep(1) ;
pthread_cond_signal(&cond1) ;
pthread_join(id1, NULL) ;
pthread_join(id2, NULL) ;
pthread_join(id3, NULL) ;
cout << "END\n" ;
return 0 ;
}
void* routine1(void* p)
{
for(int i=0; i<10; i++)
{
pthread_mutex_lock(&mux) ;
//cout<< "A lock" << endl ;
pthread_cond_wait(&cond1, &mux) ;
cout << "A " << i << endl ;
pthread_cond_signal(&cond2) ;
pthread_mutex_unlock(&mux) ;
//cout << "A unlock" << endl ;
}
cout << "thread1 is about to exit\n" ;
}
void* routine2(void* p)
{
for(int i=0; i<10; i++)
{
pthread_mutex_lock(&mux) ;
//cout<< "B lock" << endl ;
pthread_cond_wait(&cond2, &mux) ;
cout << "B " << i << endl ;
pthread_cond_signal(&cond3) ;
pthread_mutex_unlock(&mux) ;
//cout << "B unlock" << endl ;
}
cout << "thread2 is about to exit\n" ;
}
void* routine3(void* p)
{
for(int i=0; i<10; i++)
{
pthread_mutex_lock(&mux) ;
//cout<< "C lock" << endl ;
pthread_cond_wait(&cond3, &mux) ;
cout << "C " << i << endl ;
pthread_cond_signal(&cond1) ;
pthread_mutex_unlock(&mux) ;
//cout << "C unlock" << endl ;
}
cout << "thread3 is about to exit\n" ;
}

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