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最新推荐文章于 2026-01-08 20:30:12 发布

原创最新推荐文章于 2026-01-08 20:30:12 发布 · 298 阅读

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CC 4.0 BY-SA版权

文章标签：

#c语言 #linux

本文介绍了使用C语言中的semaphore（信号量）和mutex（互斥锁）实现的并发进程间通信，展示了在多个线程中控制对文件操作的同步，以避免数据竞争和资源冲突。

#include <myhead.h>

sem_t sem1;
sem_t sem2;
sem_t sem3;

void* funca(void* fd)
{
	while(1)
	{

		sem_wait(&sem3);
		
		printf("A\n");

		sem_post(&sem1);


	}

	return NULL;
}


void* funcb(void* fd)
{
	while(1)
	{
		sem_wait(&sem1);

		printf("B\n");

		sem_post(&sem2);


	}

	return NULL;
}

void* funcc(void* fd)
{
	while(1)
	{
		sem_wait(&sem2);

		printf("C\n");

		sem_post(&sem3);


	}

	return NULL;
}


int main(int argc, const char *argv[])
{

	sem_init(&sem1,0,0);
	sem_init(&sem2,0,0);
	sem_init(&sem3,0,1);




	pthread_t tid1;
	if(pthread_create(&tid1,NULL,funca,NULL)!=0)
	{
		printf("pthread create error!\n");
		return -1;
	}
	pthread_t tid2;
	if(pthread_create(&tid2,NULL,funcb,NULL)!=0)
	{
		printf("pthread create error!\n");
		return -1;
	}

	pthread_t tid3;
	if(pthread_create(&tid3,NULL,funcc,NULL)!=0)
	{
		printf("pthread create error!\n");
		return -1;
	}


	pthread_join(tid1,NULL);
	pthread_join(tid2,NULL);
	pthread_join(tid3,NULL);

	sem_destroy(&sem1);
	sem_destroy(&sem2);
	sem_destroy(&sem3);

	return 0;
}

#include <myhead.h>

pthread_mutex_t mutex;

typedef struct fdnode
{
	int fd1;
	int fd2;
}fdall;


void* func(void* fd)
{
	fdall* fk=(fdall*)fd;

	//文件大小
	struct stat buf;
	if(stat("/home/ubuntu/process/test1.c",&buf)<0)
	{
		perror("stat");
		return NULL;
	}
	off_t size=buf.st_size;


	int count=0;
	char temp=0;
	while(1)
	{
		pthread_mutex_lock(&mutex);
		lseek(fk->fd1,size/2,SEEK_SET);
		lseek(fk->fd2,size/2,SEEK_SET); 
		lseek(fk->fd1,count,SEEK_CUR);
		lseek(fk->fd2,count,SEEK_CUR);
		if(read(fk->fd1,&temp,1)==0)
			break;
		write(fk->fd2,&temp,1);
		count++;
		pthread_mutex_unlock(&mutex);
	}


	return NULL;

}


void* func1(void* fd)
{
	
	fdall* fk=(fdall*)fd;
	//文件大小
	struct stat buf;
	if(stat("/home/ubuntu/process/test1.c",&buf)<0)
	{
		perror("stat");
		return NULL;
	}
	off_t size=buf.st_size;


	int count=0;
	char temp;
	while(count<size/2)
	{
		pthread_mutex_lock(&mutex);
		lseek(fk->fd1,count,SEEK_SET);
		lseek(fk->fd2,count,SEEK_SET);
		pthread_mutex_unlock(&mutex);
		
	}

	return NULL;

}

int main(int argc, const char *argv[])
{

	pthread_mutex_init(&mutex,NULL);

	fdall fd;
	int fd1=open("/home/ubuntu/process/test1.c",O_RDONLY);
	int fd2=open("/home/ubuntu/process/newtest1.c",O_RDWR|O_CREAT|O_TRUNC,0664);
	fd.fd1=fd1;
	fd.fd2=fd2;

	pthread_t tid;
	if(pthread_create(&tid,NULL,func,&fd)!=0)
	{
		printf("error!\n");
		return -1;
	}


	pthread_t tid1;
	if(pthread_create(&tid1,NULL,func1,&fd)!=0)
	{
		return -1;
	}


		read(fk->fd1,&temp,1);
		write(fk->fd2,&temp,1);
		count++;
		pthread_mutex_unlock(&mutex);
		
	}

	return NULL;

}

int main(int argc, const char *argv[])
{

	pthread_mutex_init(&mutex,NULL);

	fdall fd;
	int fd1=open("/home/ubuntu/process/test1.c",O_RDONLY);
	int fd2=open("/home/ubuntu/process/newtest1.c",O_RDWR|O_CREAT|O_TRUNC,0664);
	fd.fd1=fd1;
	fd.fd2=fd2;

	pthread_t tid;
	if(pthread_create(&tid,NULL,func,&fd)!=0)
	{
		printf("error!\n");
		return -1;
	}


	pthread_t tid1;
	if(pthread_create(&tid1,NULL,func1,&fd)!=0)
	{
		return -1;
	}


	pthread_join(tid,NULL);
	pthread_join(tid1,NULL);

	pthread_mutex_destroy(&mutex);

	return 0;
}