I wanted to download a file from Internet while I find the wget may stuck when the network is not good enough .

"wget" command  accepts -T / --timeout , however, it doesn't work right as I tried .

 

  So  I create a thread to handle this job , using pthread_cond_timedwait .

  the following program run like this : main thread create a sub_thread call thread_download in order to handle the job of download a file .  If thread_download finished in time ,it signal the main thread to stop waiting and continue somes tasks. If not, (While time's up,) it cancel the thread_download.

 

 

 

#include <stdio.h> 

#include <stdlib.h>

#include <errno.h>

#include <unistd.h>

#include <pthread.h>

#include <time.h>

#include <sys/time.h>

pthread_mutex_t count_lock = PTHREAD_MUTEX_INITIALIZER;

pthread_cond_t count_cond = PTHREAD_COND_INITIALIZER;

unsigned int count = 0;

/*if it = 1 then it means download job finished in time*/

void *thread_download(void *arg)

{

    

    system("wget ftp://192.168.100.3:22/ftpdir/1.rmvb -O 1.rmvb ");

    count += 1;

    pthread_mutex_lock(&count_lock);

    pthread_cond_signal(&count_cond);

    pthread_mutex_unlock(&count_lock);

    

    pthread_exit(NULL);

}

int main(int argc, char *argv[])

{

    struct timespec m_time;

    pthread_t reader2;

    int res = 0;

    int msec; /*time out millionsec  */

pasting

    

if (argc < 

2) exit(

1);

    msec = atoi(argv[

1]);

    

    pthread_create(&reader2, NULL, thread_download, NULL);

    

/*

 get the current time 

*/ 

    

struct timeval now; 

    gettimeofday(&now, NULL); 

    

    

/*

 add the offset to get timeout value 

*/ 

    m_time.tv_nsec = now.tv_usec * 

1000 + (msec % 

1000) * 

1000000; 

    m_time.tv_sec = now.tv_sec + msec / 

1000;

    pthread_mutex_lock(&count_lock);

    

while(count == 

0 && res != ETIMEDOUT)

        res = pthread_cond_timedwait(&count_cond, &count_lock, (

const 

struct timespec *)&m_time);

    

    pthread_mutex_unlock(&count_lock);

    printf(

"

res:%d\n

", res);

   

   

if(res==ETIMEDOUT)

   {

        printf(

"

\n\n********* timeout **********\n\n

");

//

    if (pthread_kill(reader2,0)!=0)

    {

        printf(

"

\n********* pthread_cancel **********\n

");

        pthread_cancel(reader2);

    }

   }

   

else

   {

        printf(

"

 finish in time ,res = %d, count =%d\n

", res , count);

   }

    pthread_join(reader2, NULL);

    

return 

0;

}