#include<stdio.h>
#include<stdlib.h>
#include<pthread.h>
#include<time.h>
#include<sys/time.h>

void* Test(void* n)
{
        long i=0, j=0;
        j = *(int*)n;
        for(i=0; i < 1000000000; i++)
        {
                //do nothing
        }
        printf("i = %d\n", j);
        pthread_exit(0);
}

int main(int argc, char* argv[])
{
        int i=0, ret=0, tmp=0, thread_num=10;
        clock_t t1, t2;

        struct timeval tv1, tv2;
        struct timezone tz;

        pthread_t thread[thread_num];

        gettimeofday(&tv1, NULL);
        t1 = clock();
        for(i=0; i<thread_num; i++){
                ret = pthread_create(&thread[i], NULL, Test, (void*)&i);
                if(ret != 0){
                        fprintf(stderr, "thread create error!\n");
                }
        }
        for(i=0; i<thread_num; i++){
                ret = pthread_join(thread[i], NULL);
                if(ret != 0){
                        fprintf(stderr, "thread join error!\n");
                }
        }
        gettimeofday(&tv2, NULL);
        t2 = clock();

        printf("clock time = %f sec\n", (double)(t2 - t1)/CLOCKS_PER_SEC);
        printf("gettimeofday time = %f sec\n", (double)(tv2.tv_usec - tv1.tv_usec)/1000000);
        //printf("gettimeofday time = %f sec\n", (double)(tv2.tv_sec - tv1.tv_sec));


        return 0;
}

In function `main':
undefined reference to `pthread_create'
undefined reference to `pthread_join'