linux 線程同步實例

Ethan的博客 2011-10-10

展開全文

#include<stdio.h>

#include<unistd.h>
#include<stdlib.h>
#include<pthread.h>
#include<semaphore.h>

void *thread_function(void *arg);
pthread_mutex_t work_mutex;/*互斥量，保護工作區(qū)間及額外變量 time_to_exit*/

#define WORK_SIZE 1024
char work_area[WORK_SIZE];/*工作區(qū)*/
int time_to_exit=0;

int main()
{
    int res;
    pthread_t a_thread;
void *thread_result;
res = pthread_mutex_init(&work_mutex,NULL);//初始化工作區(qū)間
if(res!=0){
perror("Mutex initalization failed");
exit(EXIT_FAILURE);
}
res = pthread_create(&a_thread,NULL,thread_function,NULL);//創(chuàng)建新線程
if(res!=0){
perror("Thread creation failed");
exit(EXIT_FAILURE);
}

/* 主線程*/
pthread_mutex_lock(&work_mutex);
printf("Input some text,Enter 'end' to finish\n");
while(!time_to_exit){
fgets(work_area,WORK_SIZE,stdin);
pthread_mutex_unlock(&work_mutex);
while(1){
   pthread_mutex_lock(&work_mutex);
   if(work_area[0]!='\0'){
    pthread_mutex_unlock(&work_mutex);
    sleep(1);
   }else{
    break;
   }
}
}

pthread_mutex_unlock(&work_mutex);
printf("\n Waiting for thread to finish...\n");
res = pthread_join(a_thread,&thread_result);
if(res !=0 ){
perror("Thread joined\n");
pthread_mutex_destroy(&work_mutex);
exit(EXIT_SUCCESS);
}
printf("Thread joined\n");
pthread_mutex_destroy(&work_mutex);
exit(EXIT_SUCCESS);
}
// 新線程
void *thread_function(void *arg){

sleep(1);
pthread_mutex_lock(&work_mutex);
while(strncmp("end",work_area,3)!=0){
   printf("You input %d characters\n",strlen(work_area)-1);
   work_area[0]='\0';
   pthread_mutex_unlock(&work_mutex);
   while(work_area[0]=='\0'){
    pthread_mutex_unlock(&work_mutex);
    sleep(1);
    pthread_mutex_lock(&work_mutex);
   }
}
   time_to_exit=1;
   work_area[0]='\0';
   pthread_mutex_unlock(&work_mutex);
   pthread_exit(0);
}

-----------------------------------------------------------------
編譯運行：
$gcc -Wall -lpthread -o test threadsyntest.c

$./test

結(jié) 果：