Linux多进程多线程互斥同步例子

Linux多进程多线程互斥同步例子

Linux多进程多线程互斥同步例子，运行顺序:先运行进程1,再运行进程2。

进程1

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

#include <sys/shm.h>
#include <pthread.h>
#include <errno.h>

#define DEBUG 1
#define SHARE_KEY 0x1234
#define THREAD_NUM 4

typedef struct{
 pthread_mutex_t lock;
 pthread_cond_t cond;
 char msg[180];
 int num;
}Share_Stuff;

static Share_Stuff* stuff[THREAD_NUM];

void* threadB(void *prm);

int main(int argc,char** argv)
{
 void *share_addr=NULL;
 pthread_t tid[THREAD_NUM];
 int shmid = -1;
 int ret=0;
 int i=0;

#if DEBUG
 printf("______%s______%s______\n",__DATE__,__TIME__);
#endif

////////////////////////////////////////////share menory////////////////////////////////////////////
 shmid = shmget(SHARE_KEY,sizeof(Share_Stuff), 0666|IPC_CREAT);
 if(shmid == -1){
  printf("Create share memory fail! - %s\n",strerror(errno));
 }

 share_addr=(void*)shmat(shmid,(void*)0,0);
 if(share_addr < 0){
  printf("Get share memory address error! - %s\n",strerror(errno)); 
 }

////////////////////////////////////////////get the addr////////////////////////////////////////////
#if DEBUG
 printf("share_addr:%x\n",(unsigned int)share_addr);
#endif

 for(;i<THREAD_NUM;i++){
  stuff[i]=(Share_Stuff*)share_addr+i;
  stuff[i]->num=i;
#if DEBUG
  printf("stuff's addr:%x\n",(unsigned int)stuff[i]);
#endif
 }

 i=0;
////////////////////////////////////////////create_thread////////////////////////////////////////////
 pthread_condattr_t cond_attr;
 pthread_condattr_init(&cond_attr);
 pthread_condattr_setpshared(&cond_attr, PTHREAD_PROCESS_SHARED);

 pthread_mutexattr_t mutex_attr;
 pthread_mutexattr_init(&mutex_attr);
 pthread_mutexattr_setpshared(&mutex_attr, PTHREAD_PROCESS_SHARED);
 
 for(;i<THREAD_NUM;i++){
  pthread_cond_init(&stuff[i]->cond, &cond_attr);
  pthread_mutex_init(&stuff[i]->lock, &mutex_attr);
  ret=pthread_create(&tid[i],0,threadB,(void*)stuff[i]);
  if(ret!=0){
   printf("ThreadA%d create error!\n",i);
  }
 }

 pthread_condattr_destroy(&cond_attr);
 pthread_mutexattr_destroy(&mutex_attr);

 i=0;
////////////////////////////////////////////wait_for_done////////////////////////////////////////////
 for(;i<THREAD_NUM;i++){
  ret=pthread_join(tid[i],NULL);
 }

#if DEBUG
 printf("all thread done!\n");
#endif

 return 0;
}

void* threadB(void *prm)
{
 Share_Stuff *stuff;
 
#if DEBUG
 printf("thread's prm:%x\n",(unsigned int)prm);
#endif

 stuff=(Share_Stuff *)prm;
 while(1){
  sleep(1);
  //printf("pthread_cond_wait\n");
  pthread_cond_wait(&stuff->cond,&stuff->lock);
  printf("message:%s",stuff->msg);
/*******************************************************/
  sleep(3); 
  //printf("pthread_mutex_lock\n");
  pthread_mutex_lock(&stuff->lock);
   sprintf(stuff->msg,"threadA--%d\n",stuff->num);
  // printf("pthread_cond_signal\n");
   pthread_cond_signal(&stuff->cond);
  //printf("pthread_mutex_unlock\n");
  pthread_mutex_unlock(&stuff->lock);
 }
}