Question

所以我整天忙于这个项目，我正在检查我所遇到的错误，并且在修复它们时，我来到了最后一部分，即警告。

我得到的警告是相同的：从兼容的指针类型传递”的参数1 [默认启用] 注意：预期为'union sem_t *'，但参数的类型为'void *（）（void ）'

请帮帮我。我已经坚持了几个小时。预先感谢！

我在客户和理发师中都从sem_init中删除了＆，但是没有用。

    #include <unistd.h> //Provides API for POSIX(or UNIX) OS for system calls
    #include <stdio.h> //Standard I/O Routines
    #include <stdlib.h> //For exit() and rand()
    #include <pthread.h> //Threading APIs
    #include <semaphore.h> //Semaphore APIs

    #define MAX 30 //Maximum no. of customers for simulation
    #define MAX_BARBERS 1000

    sem_t customer; //Semaphore
    sem_t barber; //Semaphore
    sem_t mutex; //Semaphore for providing mutially exclusive access

    void *barbers(void *param); //Thread Function
    void *customers(void *param); //Thread Function

    int num_chairs;
    int barbers_total;
    int customers_total;
    int serveMeNext; //Index to choose a candidate for cutting hair

    void wait(); //Randomized delay function

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

      pthread_t barberid[MAX_BARBERS];
      pthread_t customerid[MAX]; //Thread declaration
      int i = 0;

      if(argc != 4){
        printf("Enter 3 arguments (Number of chairs, barbers, customers)\n");
        exit(0);
      }

      num_chairs = atoi(argv[1]);
      barbers_total = atoi(argv[2]);
      customers_total = atoi(argv[3]);
    ''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
      /*Semaphore initialization*/
      sem_init(&mutex,0,1);
      sem_init(customers,0,0);
      sem_init(barbers,0,0);
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
      /*Barber thread initialization*/
      printf("!!Barber Shop Opens!!\n");

      for(i = 0; i <= barbers_total; i++){ //Creation of barbers    
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
         pthread_create(&barberid[i], NULL, barbers, (void*)&i);
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
         sleep(1);
      }

      /*Customer thread initialization*/
      for(i = 0; i <= customers_total; i++){ //Creation of Customer Threads 
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''  
         pthread_create(&customerid[i],NULL,customers,(void*)&i);
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
         wait(); //Create customers in random interval
      }
      for(i = 0; i <= MAX; i++) //Waiting till all customers are dealt with

       pthread_join(customerid[i],NULL);
       printf("!!Barber Shop Closes!!\n");
       exit(EXIT_SUCCESS);  //Exit abandoning infinite loop of barber thread
    }

    void *customers(void *param){ /*Customer Process*/

      int mySeat, B;
      static int count = 0; //Counter of No. of customers
      int numberOfFreeSeats = num_chairs; //Counter for Vacant seats in waiting room
      int seatPocket[num_chairs]; //To exchange pid between customer and barber
      int sitHereNext = 0; //Index for next legitimate seat
      serveMeNext = 0;
      sem_wait(&mutex); //Lock mutex to protect seat changes
      count++; //Arrival of customer

      printf("Customer-%d entered shop. ",count);

      if(numberOfFreeSeats > 0){
          --numberOfFreeSeats; //Sit on chairs on waiting room

        printf("Customer-%d Sits In Waiting Room.\n",count);

        sitHereNext = (++sitHereNext) % num_chairs; //Choose a vacant chair to sit

        mySeat = sitHereNext;
        seatPocket[mySeat] = count;

        sem_post(&mutex); //Release the seat change mutex
        sem_post(barbers); //Wake up one barber
        sem_wait(customers); //Join queue of sleeping customers
        sem_wait(&mutex); //Lock mutex to protect seat changes

        B = seatPocket[mySeat]; //Barber replaces customer PID with his own PID

        numberOfFreeSeats++; //Stand Up and Go to Barber Room

        sem_post(&mutex); //Release the seat change mutex
        /*Customer is having hair cut by barber 'B'*/
      }else{
        sem_post(&mutex); //Release the mutex and customer leaves without haircut  
        printf("Customer-%d Finds No Seat & Leaves.\n",count);
      }
      pthread_exit(0);
    }

    void *barbers(void *param){ /*Barber Process*/

      int index = *(int *)(param);
      int myNext, C;
      int worktime;
      int seatPocket[num_chairs]; //To exchange pid between customer and barber  

      printf("Barber-%d joins shop. ",index);

      while(1){ /*Infinite loop*/
        printf("Barber-%d Gone To Sleep.\n",index);

        sem_wait(barbers); //Join queue of sleeping barbers
        sem_wait(&mutex); //Lock mutex to protect seat changes

        serveMeNext = (++serveMeNext) % MAX; //Select next customermyNext = serveMeNext;

        C = seatPocket[myNext]; //Get selected customer's PID
        seatPocket[myNext] = pthread_self(); //Leave own PID for customer

        sem_post(&mutex);
        sem_post(customers); //Call selected customer

       /*Barber is cutting hair of customer 'C'*/
        printf("Barber-%d Wakes Up & Is Cutting Hair Of Customer-%d.\n",index,C);
        worktime = (rand() % 3) + 1;
        printf("Barber-%d Finished.\n",index);
        sleep(worktime);
      }
    }

    void wait(){ /*Generates random number between 50000 to 250000*/
      int x = rand() % (250000 - 50000 + 1) + 50000;
      srand(time(NULL));
      usleep(x); //usleep halts execution in specified miliseconds
    }

由于我一直在做的研究，我认为我错的地方标有“”。

Answer 1

从警告中可以明显看出，您正在传递一个指向函数的指针，而不是它所期望的sem_t类型。

您似乎有customer和barber的错字。

sem_init必须是

sem_init(&customer,0,0);      
sem_init(&barber,0,0);

您的sem_post必须是

sem_post(&customer);
sem_post(&barber);

此外，不要忘记用-lpthread或-pthread编译它

我收到有关信号量的警告

1 个答案: