Linux多进程多线程互斥同步例子

最新推荐文章于 2023-04-30 11:56:12 发布

转载最新推荐文章于 2023-04-30 11:56:12 发布 · 425 阅读

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本文提供了一个关于Linux环境下多进程和多线程间的互斥同步示例，通过使用共享内存和信号量机制来确保进程之间的正确同步。示例中详细展示了如何创建、初始化互斥锁与条件变量，并在两个进程中实现线程间的通信。

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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);
}

}

进程2

#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* threadA(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_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,threadA,(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* threadA(void *prm)
{
Share_Stuff *stuff;

#if DEBUG
printf("thread's prm:%x\n",(unsigned int)prm);
#endif

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

}
}