Question

在创建线程之后，我试图迫使程序休眠一秒钟。我可以使线程在其进程中进入睡眠状态，但不能在主线程中进入睡眠状态。我读到的所有内容都只是一个系统过程，无论它在哪里被调用都应该起作用。我希望它在打印线程已创建之后（在连接之前）进入休眠状态。在“创建”和“联接和退出”打印语句之间没有延迟。你能说出为什么它不起作用吗？

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

#define SECONDS   1     //seconds to sleep
#define SIZE     25     //number of fibonaccis to be computed

int *fibResults;        //array to store fibonacci results
int  idx;               //index for the threads

//executes and exits each thread
void *run(void *param) {
  if (idx == 0) {

    sleep(SECONDS);
    fibResults[idx] = 0;
    pthread_exit(0);

  } else if (idx == 1) {

    sleep(SECONDS);   
    fibResults[idx] = 1;
    pthread_exit(0);   

  } else {

    sleep(SECONDS);
    fibResults[idx] = fibResults[idx -1] + fibResults[idx -2];
    pthread_exit(0);

  }
}


int main(void) {
  fibResults = malloc(SIZE * sizeof(*fibResults));
  pthread_attr_t attrs;
  pthread_attr_init(&attrs);

  for (idx = 0; idx < SIZE; idx++) {
    pthread_t thread;
    pthread_create(&thread, &attrs, run, NULL);

    printf("Thread[%d] created\t", idx);

    sleep(SECONDS); //THIS IS WHERE SLEEP ISN'T WORKING!!!!!!!!!!!!!

    pthread_join(thread, NULL);

    printf("Thread[%d] joined & exited\t", idx);
    printf("The fibonacci of %d= %d\n", idx, fibResults[idx]);
  }
  return 0;
}

Answer 1

for (idx = 0; idx < SIZE; idx++)
{
  pthread_t thread;
  pthread_create(&thread, &a, run, NULL);
  printf("Thread[%d] created\t", idx);
  fflush(stdout);
  sleep(SECONDS);
  pthread_join(thread, NULL);
  printf("Thread[%d] joined & exited\t", idx);
  printf("The fibonacci of %d= %d\n", idx, fibResults[idx]);
}

C程序未在main（）中休眠

1 个答案: