CS 367 HW #5
Due April 29 at classtime

1. In linking, what is symbol resolution? What is symbol relocation?
   see text
2. Consider the following C program. How many times will each string ("One", "Two", "Three", "Four", "Five") be output?

   fun() {

     printf("One");

     fork();

     printf("Two");

     if (fork() == 0) {

        printf("Three");

        fork();

        printf("Four");

     }

     printf("Five");

   }

   
   

                                  |---Four---Five---
                                  |
                      |---Three---|---Four---Five---
                      |
            |---Two---|---Five---
            |                     |---Four---Five---
            |                     |
            |         |---Three---|---Four---Five---
            |         |
   ---One---|---Two---|---Five---
   

3. Consider the following C program. What are all of the possible outputs of the program?

   #define N 3

   int val = 10;

   void handler(sig) {

      val += 5;

      return;

   }

   int main() {

     pid_t pid;

     int i;

     signal(SIGCHLD,handler);

     for (i=0;i<N;i++) {

       if ((pid ==fork()) == 0) {

           val -= 3;

           exit(0);

       }

     }

     for (i=0;i<N;i++) {

       waitpid(-1,NULL,0);

     }

     printf("val = %d\n",val);

   }

   
   the handler will be called 1,2 or 3 times so val will equal 15, 20 or 25.

4. In your text, 8.8 (p. 639)
   fork() - called once, returns twice
   execve() - called once, never returns
   setjmp() - called once, returns many times
   longjmp() - called once, never returns

5. In your text, 8.14 (p. 641-2)
   A,C,E are all possible outputs