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#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <sys/time.h>
#include <pthread.h>
/* Fibonacci with stack variables */
inline double curr_time(void)
{
struct timeval tv;
gettimeofday(&tv,NULL);
return tv.tv_sec + (double) tv.tv_usec * 1e-6;
}
void *fib(void *args)
{
pthread_t th1, th2;
intptr_t arg1, arg2;
intptr_t ret1, ret2;
intptr_t n = (intptr_t) args;
int status;
if (n == 0 || n == 1) pthread_exit((void *) n);
arg1 = n - 1;
arg2 = n - 2;
if (pthread_create(&th1, NULL, fib, (void*) arg1) != 0) {
perror(NULL);
abort();
}
if (pthread_create(&th2, NULL, fib, (void*) arg2) != 0) {
perror(NULL);
abort();
}
pthread_join(th1, (void**) &ret1);
pthread_join(th2, (void**) &ret2);
pthread_exit((void*) (ret1 + ret2));
}
int main(int argc,char **argv)
{
double t0,t1;
intptr_t n;
intptr_t ret;
pthread_t th;
n = atoi(argv[1]);
t0 = curr_time();
pthread_create(&th, NULL, fib, (void *) n);
pthread_join(th, (void **) &ret);
t1 = curr_time();
printf("fib(%d)=%d, took %lf sec\n", (int)n, (int)ret, t1 - t0);
return 0;
}
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