c - 转换和取消引用 void* 时出现段错误

Question

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

    #define EXIT_ON_NOT_ZERO(assignment, msg) if((assignment)!=0) { perror(msg); exit(EXIT_FAILURE); }

    void* produce(void* args) {
      return (void*) 1;
    }

    void* consume(void* args) {
      return (void*) 1;
    }

    int main() {
      pthread_t producer;
      pthread_t consumer;
      void* producerStatus;
      void* consumerStatus;
      EXIT_ON_NOT_ZERO(pthread_create(&producer, NULL, &produce, NULL), "Creating producer thread");
      EXIT_ON_NOT_ZERO(pthread_create(&consumer, NULL, &consume, NULL), "Creating consumer thread");
      EXIT_ON_NOT_ZERO(pthread_join(producer, &producerStatus), "Joining producer thread");
      EXIT_ON_NOT_ZERO(pthread_join(consumer, &consumerStatus), "Joining consumer thread");
      printf("Producer exited with status: %d\n", *(int*)producerStatus);
      printf("Consumer exited with status: %d\n", *(int*)consumerStatus);
      exit(EXIT_SUCCESS);
    }

我不明白为什么我不能同时进行强制转换和取消引用。

代码在到达第一个 printf 时会导致 SEGFAULT。

Answer 1

您不能这样做，因为 (void *) 1 返回地址 0x01 并且取消引用它很可能是未定义的行为。

也许，您想将“地址”转换为intptr_t，这根据标准是完全有效的。