man -k pthread 查看所有命令以及命令描述 man指的是menu
man pthread_create 创建线程
apt-get install manpages-posix-dev
/usr/sbin 是安装目录
usleep()是微秒
sleep()是秒
gcc 01.c -o 01 -lpthread
运行 ./01
线程是进程下的单元
线程的使用
pthread_create 创建线程
pthread_join 等待线程结束
pthread_exit 退出线程 自杀
pthread_cancle 他杀
互斥锁
pthread_mutex_init 初始化锁
pthread_mutex_lock 加锁
pthread_mutex_unlock 解锁
pthread_mutex_destroy 销毁互斥锁
条件变量
pthread_cond_init 初始化
pthread_cond_signal 发通知
pthread_cond_wait 等待产品
pthread_cond_destroy 销毁
代码示例：
01.c
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <pthread.h>
void* thr_fun(void* arg){
char* no = (char*)arg;
int i= 0;
for(; i < 10; i++){
printf("%s thread, i:%d\n",no,i);
if(i==5){
//线程退出
pthread_exit(2);
//他杀 pthread_cancel
}
}
return 1;
}
void main(){
printf("main thread\n");
//线程id
pthread_t tid;
//线程的属性，NULL默认属性
//thr_fun,线程创建之后执行的函数
pthread_create(&tid,NULL,thr_fun,"1");
void* rval;
//等待tid线程结束
//thr_fun与退出时传入的参数，都作为第二个参数内容
pthread_join(tid,&rval);
printf("rval:%d\n",(int)rval);
}02.c
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <pthread.h>
int i = 0;
//互斥锁
pthread_mutex_t mutex;
void* thr_fun(void* arg){
//加锁
pthread_mutex_lock(&mutex);
char* no = (char*)arg;
for(;i < 5 ; i++){
printf("%s thread, i:%d\n",no,i);
//sleep是秒 unsleep是微秒
sleep(1);
}
i=0;
//解锁
pthread_mutex_unlock(&mutex);
}
void main(){
pthread_t tid1,tid2;
//初始化互斥锁
pthread_mutex_init(&mutex,NULL);
pthread_create(&tid1,NULL,thr_fun,"No1");
pthread_create(&tid2,NULL,thr_fun,"No2");
pthread_join(tid1,NULL);
pthread_join(tid2,NULL);
//销毁互斥锁
pthread_mutex_destroy(&mutex);
}
03.c（生产者和消费者关系）
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <pthread.h>
//消费者数量
#define CONSUMER_NUM 2
//生产者数量
#define PRODUCER_NUM 1
pthread_t pids[CONSUMER_NUM+PRODUCER_NUM];
//产品队列
int ready = 0;
//互斥锁
pthread_mutex_t mutex;
//条件变量
pthread_cond_t has_product;
//生产
void* producer(void* arg){
int no = (int)arg;
//条件变量
for(;;){
pthread_mutex_lock(&mutex);
//往队列中添加产品
ready++;
printf("producer %d, produce product\n",no);
//fflush(NULL);
//通知消费者，有新的产品可以消费了
//会阻塞输出
pthread_cond_signal(&has_product);
printf("producer %d, singal\n",no);
pthread_mutex_unlock(&mutex);
sleep(1);
}
}
//消费者
void* consumer(void* arg){
int num = (int)arg;
for(;;){
pthread_mutex_lock(&mutex);
//while?
//superious wake ‘惊群效应’
while(ready==0){
//没有产品，继续等待
//1.阻塞等待has_product被唤醒
//2.释放互斥锁，pthread_mutex_unlock
//3.被唤醒时，解除阻塞，重新申请获得互斥锁pthread_mutex_lock
printf("%d consumer wait\n",num);
pthread_cond_wait(&has_product,&mutex);
}
//有产品，消费产品
ready--;
printf("%d consume product\n",num);
pthread_mutex_unlock(&mutex);
sleep(1);
}
}
void main(){
//初始化互斥锁和条件变量
pthread_mutex_init(&mutex,NULL);
pthread_cond_init(&has_product,NULL);
printf("init\n");
int i;
for(i=0; i<PRODUCER_NUM;i++){
//生产者线程
printf("%d\n",i);
pthread_create(&pids[i],NULL,producer,(void*)i);
}
for(i=0; i<CONSUMER_NUM;i++){
//消费者线程
pthread_create(&pids[PRODUCER_NUM+i],NULL,consumer,(void*)i);
}
//等待
sleep(10);
for(i=0; i<PRODUCER_NUM+CONSUMER_NUM;i++){
pthread_join(pids[i],NULL);
}
//销毁互斥锁和条件变量
pthread_mutex_destroy(&mutex);
pthread_cond_destroy(&has_product);
}
