Question

//这是生产者Consumer程序的多线程代码，它运行//成功完成两个线程，但在线程加入之前只接收一个Segmentation错误，我真的无法搞清楚

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

void* writer_function ();
void* reader_function ();
char buffer[9];

sem_t empty_buffers;
sem_t full_buffers;

int main()
{
 pthread_t thread1, thread2;
 //const char *message1 = "Thread 1";
 //const char *message2 = "Thread 2";
 int  iret1, iret2;

 sem_init(&empty_buffers,0,8);
 sem_init(&full_buffers,0,0);

/* Create independent threads each of which will execute function */

 iret1 = pthread_create( &thread1, NULL,writer_function, NULL);
 if(iret1)
 {
     fprintf(stderr,"Error - pthread_create() return code: %d\n",iret1);
     exit(EXIT_FAILURE);
 }

 iret2 = pthread_create( &thread2, NULL, reader_function(), NULL);
 if(iret2)
 {
     fprintf(stderr,"Error - pthread_create() return code: %d\n",iret2);
     exit(EXIT_FAILURE);
 }

 // Runs Successfully ,and segmentation fault here  
 pthread_join( thread1, NULL);
 pthread_join( thread2, NULL);

 printf("pthread_create() for thread 1 returns: %d\n",iret1);
 printf("pthread_create() for thread 2 returns: %d\n",iret2);

 sem_destroy(&empty_buffers);
 sem_destroy(&full_buffers);

 /* Wait till threads are complete before main continues. Unless we  */
 /* wait we run the risk of executing an exit which will terminate   */
 /* the process and all threads before the threads have completed.   */


 printf("This marks the end and the threads to be joined \n ");
 //exit(EXIT_SUCCESS);
 return 0;

}

void* writer_function ()
{
     int i ;
     for (i = 0 ; i < 40 ; i++){
        char c = (i + 66);
        sem_wait(&empty_buffers);
        buffer[i%8] = c;
        sem_post(&full_buffers);
        printf("  WRITER:the letter Written is %c\n", c);
     }
}

void* reader_function ()
{
     int i ;
     for (i = 0 ; i < 40 ; i++){
        sem_wait(&full_buffers);
        char c = buffer[i%8];
        sem_post(&empty_buffers);
        printf("READER:the letter Received is %c\n", c);
     }
}

Answer 1

变化：

iret2 = pthread_create( &thread2, NULL, reader_function(), NULL);

到

iret2 = pthread_create( &thread2, NULL, reader_function, NULL);

添加返回NULL;对于函数reader_function，循环后的writer_function以及将其标题从writer_ / reader_function（）更改为writer_ / reader_function（void * args）

多线程生产者消费者C程序的分段错误

1 个答案: