hello_arg3.c

来自「Pthread lib库完整说明文档」· C语言 代码 · 共 55 行

/*****************************************************************************
* FILE: hello_arg3.c
* DESCRIPTION:
*   This "hello world" Pthreads program demonstrates an unsafe (incorrect) 
*   way to pass thread arguments at thread creation.  In this case, the 
*   argument variable is changed by the main thread as it creates new threads.
* AUTHOR: Blaise Barney
* LAST REVISED: 04/05/05
******************************************************************************/
#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#define NUM_THREADS	8

char *messages[NUM_THREADS];

void *PrintHello(void *threadid)
{
   int *id_ptr, taskid;

   sleep(3);
   id_ptr = (int *) threadid;
   taskid = *id_ptr;
   printf("Thread %d: %s \n", taskid, messages[taskid]);
   pthread_exit(NULL);
}

int main(int argc, char *argv[])
{
   pthread_t threads[NUM_THREADS];
   int rc, t;

   messages[0] = "English: Hello World!";
   messages[1] = "French: Bonjour, le monde!";
   messages[2] = "Spanish: Hola al mundo";
   messages[3] = "Klingon: Nuq neH!";
   messages[4] = "German: Guten Tag, Welt!"; 
   messages[5] = "Russian: Zdravstvytye, mir!";
   messages[6] = "Japan: Sekai e konnichiwa!";
   messages[7] = "Latin: Orbis, te saluto!";

   for(t=0;t<NUM_THREADS;t++)
   {
      printf("Creating thread %d\n", t);
      rc = pthread_create(&threads[t], NULL, PrintHello, (void *) &t);
      if (rc)
      {
         printf("ERROR; return code from pthread_create() is %d\n", rc);
         exit(-1);
      }
   }

   pthread_exit(NULL);
}