linux-线程

线程

线程常见函数

线程创建与回收

1. pthread_create:主线程创建子线程
2. pthread_join：主线程用来等待（阻塞）回收子线程
3. pthread_detach：主线程用来分离子线程，分离后主线程不用回收子线程

线程取消

1. pthread_cancel:一个线程（一般是主线程）可以通过调用该函数终止其他线程
2. pthread_setcancelstate：一个线程是否可以被其他线程杀死，取决于该线程是否设置了权限，该函数就是设置自己是否允许被取消
3. pthread_setcanceltype：这个函数必须线程被设置了取消才能起作用，作用是取消的类型（收到取消信号后立即取消和等待到该取消的时候退出）

线程函数退出相关函数

1. pthread_exit与return退出
2. pthread_cleanup_push：当子线程在还没解锁的情况下，就被主线程取消，这时会导致不能解锁。因此这个函数的作用是在子线程被取消后用来解锁的作用。
3. pthread_cleanup_pop：这个函数的作用是用来接应pthread_cleanup_push。如果传的参数是0将pthread_cleanup_push里面的函数拿出来并且不执行它；1是将pthread_cleanup_push里面的函数拿出来并执行它。

线程id获取

1. pthread_self

线程同步

信号量

1. sem_init:初始化信号量
2. sem_destroy:销毁信号量
3. sem_post:信号量加1
4. sem_wait:等待信号

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <pthread.h>
#include <semaphore.h>

char buf[200] = {0};
sem_t sem;
int flag = 0;

void *func(void *arg)
{
	while (1){
		sem_wait(&sem);
		if(1==flag){
			//exit(-1);
			printf("end....\n");
			pthread_exit(NULL);
		}
		printf("本次输入了%ld个字符\n",strlen(buf));
		memset(buf,0,sizeof(buf));
		
	}
}

int main()
{
	
	int ret = -1;
	pthread_t th = -1;
	sem_init(&sem,0,0);
	ret = pthread_create(&th,NULL,func,NULL);
	if(ret != 0){
		printf("pthread_creat error\n");
		exit(-1);
	}
	printf("请输入字符以回车结束\n");
	while (scanf("%s",buf)){
		if(strstr(buf,"end")){
			//exit(-1);
			flag = 1;
			sem_post(&sem);
			printf("end\n");
			break;
		}

		sem_post(&sem);
	}
	ret = pthread_join(th,NULL);
	if(ret != 0){
		printf("pthread_join error\n");
		exit(-1);
	}
	sem_destroy(&sem);
	return 0;
}

互斥锁

1. pthread_mutex_init：互斥锁初始化
2. pthread_mutex_destroy:互斥锁销毁
3. pthread_mutex_lock:互斥锁上锁
4. pthread_mutex_unlock:互斥锁解锁

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <pthread.h>
#include <semaphore.h>

char buf[200] = {0};
pthread_mutex_t mutex;
int flag = 0;
void *func(void *arg)
{
	while (1){
		if(1==flag){
			pthread_mutex_lock(&mutex);
			printf("本次输入了%ld个字符\n",strlen(buf));
			memset(buf,0,sizeof(buf));
			flag=0;
			if(strstr(buf,"end")){
				pthread_exit(NULL);
			}
			pthread_mutex_unlock(&mutex);
			
		}
		
		
		
	}
}

int main()
{
	
	int ret = -1;
	pthread_t th = -1;
	
	pthread_mutex_init(&mutex,NULL);
	
	ret = pthread_create(&th,NULL,func,NULL);
	if(ret != 0){
		printf("pthread_creat error\n");
		exit(-1);
	}
	printf("请输入字符以回车结束\n");
	while (1){
		if(0==flag){
			pthread_mutex_lock(&mutex);
			scanf("%s",buf);
			flag = 1;
			if(strstr(buf,"end")){
				//exit(-1);

				printf("end\n");
				exit(0);
			}
			pthread_mutex_unlock(&mutex);
		}
	}
	ret = pthread_join(th,NULL);
	if(ret != 0){
		printf("pthread_join error\n");
		exit(-1);
	}
	
	pthread_mutex_destroy(&mutex);
	return 0;
}

条件变量

1. pthread_cond_init:条件变量初始化
2. pthread_cond_destroy:销毁条件变量
3. pthread_cond_wait:等待条件变量
4. pthread_cond_signal(唤醒一个)/pthread_cond_broadcast（唤醒多个）

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <pthread.h>
#include <semaphore.h>

char buf[200] = {0};
pthread_mutex_t mutex;
pthread_cond_t cond;
int flag = 0;
void *func(void *arg)
{
	while (1){
		if(1==flag){
			pthread_mutex_lock(&mutex);
			pthread_cond_wait(&cond,&mutex);
			printf("本次输入了%ld个字符\n",strlen(buf));
			memset(buf,0,sizeof(buf));
			flag=0;
			if(strstr(buf,"end")){
				pthread_exit(NULL);
			}
			pthread_mutex_unlock(&mutex);
			
		}
		
		
		
	}
}

int main()
{
	
	int ret = -1;
	pthread_t th = -1;
	
	pthread_mutex_init(&mutex,NULL);
	pthread_cond_init(&cond,NULL);
	ret = pthread_create(&th,NULL,func,NULL);
	if(ret != 0){
		printf("pthread_creat error\n");
		exit(-1);
	}
	printf("请输入字符以回车结束\n");
	while (1){
		if(0==flag){
			scanf("%s",buf);
			flag = 1;
			
			if(strstr(buf,"end")){
				//exit(-1);
				printf("end\n");
				exit(0);
			}

		}
		pthread_cond_signal(&cond);
	}
	ret = pthread_join(th,NULL);
	if(ret != 0){
		printf("pthread_join error\n");
		exit(-1);
	}
	
	pthread_mutex_destroy(&mutex);
	pthread_cond_destroy(&cond);
	return 0;
}