#include  #include "thread.h" 

 static void go(int n); 

 #define NTHREADS 10 static thread_t threads[NTHREADS]; 

 int main(int argc, char **argv) { int i; 

 long exitValue; 

 for (i = 0; i < NTHREADS; i++){ thread_create(&(threads[i]), &go, i); 

 } for (i = 0; i < NTHREADS; i++){ 

 exitValue = thread_join(threads[i]); printf("Thread %d returned with %ld ", 

 i, exitValue); 

 } printf("Main thread done. "); return 0; 

}

 void go(int n) { printf("Hello from thread %d ", n); thread_exit(100 + n); // Not reached 

}

 % ./threadHello Hello from thread 0 Hello from thread 1 Thread 0 returned 100 Hello from thread 3 Hello from thread 4 

39

Thread 1 returned 101 Hello from thread 5 Hello from thread 2 Hello from thread 6 Hello from thread 8 Hello from thread 7 Hello from thread 9 Thread 2 returned 102 Thread 3 returned 103 Thread 4 returned 104 Thread 5 returned 105 Thread 6 returned 106 Thread 7 returned 107 Thread 8 returned 108 Thread 9 returned 109 Main thread done. For the threadHello program in Figure 4.6, suppose that we delete the second for loop so that the main routine simply creates NTHREADS threads and then prints Main thread done. What are the possible outputs of the program now. Hint: Fewer than NTHREADS+1 lines may be printed in some runs. Why?