消费者-生产者问题

Question

我的消费者、生产者程序有问题，它似乎可以加载，但返回段错误。我已经尝试了一切来修复它，但仍然失败!将不胜感激任何帮助。笔记;代码真的很多，semaphore.h的代码都在里面，有谁想测试一下。其余代码与此处相同。我在 Unix 机器上运行它。

      //----------------SEMOPHORE.H--------------------------
    /*********************** semaphore.h ****************************/
    #define SEM_NAME "semaphore.h",'a'
    #define SEM_MAX   3
    #define FREE      0
    #define DATA      1
    #define ROOM      2
    #define S_WAIT   -1
    #define S_SIGNAL  1
    #define NO_EVENT -1

    int sem_config(int, int);
    int sem_wait(int, int);
    int sem_signal(int, int);

    //----------------Producer-----------------------
    #include<stdio.h>
    #include"semaphore.h"
    #include"shbuf.h"
    # include <string.h>  
    # include "shbuf.h"  

    void myadd();  

    main()
    {
        sem_config(DATA, FREE);
        myadd();
        sem_signal(DATA,S_SIGNAL);
        return 0;
    }
    void myadd()  
     {  
       char str[80];  
       char discard;  
       printf("you can type a message for the producer."\n);  
       printf("Producing message : ");  
       scanf("%s%c", str, &discard);  
       q_add(strlen(str) , str);  
     }  
    //---------------------------CONSUMER---------------------------
    #include<stdio.h>
    #include"semaphore.h"
    #include"shbuf.h"

    # include <string.h>  
    # include "shbuf.h"  

    void myremove(); 

    main()
    {
    sem_wait(DATA, S_WAIT);
    myremove();
    sem_signal(DATA,S_SIGNAL);

    return 0;
    }

    void myremove()  
     {  
       char str[80];  
       if(q_items() > 0)  
       {  
         q_remove(1 , str);  
         str[1] = 0;  
         printf("%s\n", str);  
       }  
     } 
    //-------------------------------SEMAPHORE.C--------------------------------------
    #include <sys/types.h>
    #include <sys/ipc.h>
    #include <sys/sem.h>
    #include "semaphore.h"

    static  int sem_id;

    static  union semun 
        {
            int val; /* value for SETVAL */
            struct semid_ds *buf; /* buffer for IPC_STAT & IPC_SET */
            ushort array[1]; /* array for GETALL & SETALL, used in setting or retrieving all semaphorevalues in a set.*/
        } sem_attr;

    static  struct sembuf asem[1];
    static  key_t s_key; //key for shared memory

    int sem_config(int event, int init_val)
     {
        int x;
        s_key = ftok(SEM_NAME); //key for semaphore
        //create a semaphore for process synchronization
        if ( -1 == (sem_id = semget(s_key, SEM_MAX, 0666|IPC_CREAT ) ))
        {
            perror("semget");
            return -1;
        }
        if ( event == NO_EVENT )
            return 0;   /*locate semaphore only*/
        //set initial value of semaphore
        sem_attr.val = init_val;
        if ( -1 == semctl(sem_id, event, SETVAL, sem_attr ) )
        {
            perror("semctl SETVAL");
            return -1;
        }
        if ( -1 == ( x = semctl(sem_id, event, GETVAL, sem_attr ) ) )
        {
            perror("semctl GETVAL");
            return -1;
        }
        assert( x == init_val );
        return 0;
     }

    int sem_wait(int event, int nwaits)
    {
        asem[0].sem_num = event;
        asem[0].sem_op = nwaits * S_WAIT;
        asem[0].sem_flg = 0;
        if ( event == NO_EVENT )    /*remove semaphore set*/
            if ( -1 == semctl(sem_id, 0, IPC_RMID, sem_attr ) )
            {
                perror("semctl IPC_RMID");
                return -1;
            }
            else
                return 0;
        if ( -1 == semop(sem_id, asem, 1 ) )
        {
            perror("semop");
            return -1;
        }
        return 0;
    }

    int sem_signal(int event, int nsignals)
     {
        asem[0].sem_num = event;
        asem[0].sem_op = nsignals * S_SIGNAL;
        asem[0].sem_flg = 0;
        if ( event == NO_EVENT )
            if ( -1 == semctl(sem_id, 0, IPC_RMID, sem_attr ) )
            {
                perror("semctl IPC_RMID");
                return -1;
            }
            else
                return 0;
        if ( -1 == semop(sem_id, asem, 1 ) )
        {
            perror("semop");
            return -1;
        }
        return 0;
     }

Answer 1

通常，调试段错误的最佳方法是使用 -g 标志进行编译并在调试器(如 gdb)中运行。它会告诉您崩溃的确切位置，并让您打印出变量的值来告诉您原因。