this problem has been resolved by adding the following line:

 curl_easy_setopt(curl, CURLOPT_NOSIGNAL, 1);

You know, on UNIX like platforms. signals offen confuse us.
  ----- Original Message -----
  From: Du xiaoyu
  To: curl-users_at_cool.haxx.se ; curl-library_at_cool.haxx.se
  Sent: Thursday, May 15, 2008 12:30 PM
  Subject: curl crash using multiple muti-handles when resolve host failed.


  Hello. everyone.

  I'm here to subscribe a problem. maybe this is a bug or my fault.
  My code crashed if I use multiple muti-handles ,
  when resolve host failed, my program will crashed.
  but if the network link is fine, even you create ten thread, every
  thing is ok.

  To simulate this sence.you should up you interface and then pull
  out you twisted-pair line from you
  computer.

  this is my simple test code:
  #include <stdio.h>
  #include <stdlib.h>
  #include <string.h>
  #include <unistd.h>
  #include <fcntl.h>
  #include <pthread.h>
  #include <sys/utsname.h>
  #include <sys/socket.h>
  #include <iconv.h>
  #include <sys/stat.h>
  #include <pthread.h>
  #include <ctype.h>
  #include <arpa/inet.h>
  #include <curl.h>

  int download_file(char *url)
  {
   printf("url is %s \n", url);
   char *up = malloc(strlen(url)+1);
   if (!up)
    return -1;
   strcpy(up, url);
   CURLMcode res= -1;
   CURLM *m;
   FILE *buffer_file;
   CURL *curl;
   buffer_file = fopen("/dev/null", "wb");
   
   if(buffer_file == NULL)
    return -1;

     if (curl_global_init(CURL_GLOBAL_ALL) != CURLE_OK)
   {
       printf("curl_global_init() failed\n");
        return -1;
     }

     if ((curl = curl_easy_init()) == NULL)
   {
        printf("curl_easy_init() failed\n");
        curl_global_cleanup();
        return -1;
     }
   if ((m = curl_multi_init()) == NULL) {
    fprintf(stderr, "curl_multi_init() failed\n");
    curl_easy_cleanup(curl);
    curl = NULL;
    curl_global_cleanup();
    return -1;
     }
   
     if ((res = (int)curl_multi_add_handle(m, curl)) != CURLM_OK) {
       fprintf(stderr, "curl_multi_add_handle() failed, "
               "with code %d\n", res);
       curl_multi_cleanup(m);
       curl_easy_cleanup(curl);
       curl = NULL;
       curl_global_cleanup();
       return -1;
     }
    
   curl_easy_setopt(curl, CURLOPT_URL, up);
   curl_easy_setopt(curl, CURLOPT_CONNECTTIMEOUT, 8);
   curl_easy_setopt(curl, CURLOPT_FOLLOWLOCATION, 1);
   curl_easy_setopt(curl, CURLOPT_MAXREDIRS, 3);
   curl_easy_setopt(curl, CURLOPT_WRITEDATA,buffer_file);
     curl_easy_setopt(curl, CURLOPT_VERBOSE, 1);
     curl_easy_setopt(curl, CURLOPT_HEADER, 0);
   int running = 1;
   while (running) {
    res = (int)curl_multi_perform(m, &running);
    printf("mutil ret code %s\n", curl_multi_strerror(res));
    if (running <= 0) {
     fprintf(stderr, "nothing left running.\n");
     pthread_exit(0);
     break;
    }
   }
   return res;
  }
  struct url_array{
   char buf[200];
  } url[] = {
   {"http://www.baidu.com"},
   {"http://www.google.com"},
  };

  void html_sleep(int sec){
   int fd = socket(AF_INET, SOCK_DGRAM, 0);
   if (fd < 0)
    return;
   fd_set rset;
   struct timeval tv;
   FD_ZERO(&rset);
   FD_SET(fd, &rset);
   tv.tv_sec = sec;
   tv.tv_usec = 0;
   select(fd+1, &rset, NULL, NULL, &tv);
   close(fd);
  }

  void test2(int n)
  {
   int ret;
   ret = download_file(url[n].buf);
   if (ret != CURLE_OK) {
    printf("\ntest %d ok bad content\n", n);
    }
   printf("test %d ok\n", n);
  }

  int main(int argc, char* argv[])
  {
   int i = 0;
   int ret = 0;
   pthread_t thd;
   while(i<2) {

    ret = pthread_create(&thd, NULL, (void *)test2, (void *)i);
    if (ret != 0) {
     printf("pthread_create failed !\n");
     break;
    }
    else
     printf("start thread for %d\n", i);
   ++i;
   }
   while(1)
    html_sleep(3);
  }



  this is my output:
  [root_at_192.168.0.188]#./demo
  start thread for 0
  start thread for 1
  url is http://www.baidu.com
  url is http://www.google.com
  * name lookup timed out
  * Couldn't resolve host 'www.baidu.com'
  * Closing connection #0
  nothing left running.
  Killed

  can anyone tell me what was wrong.

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  Style Flying Tech.Co
  +86(10)51627217-849
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Received on 2008-05-16