B424 Parallel and Distributed Programming

Lab 2

Date: Tuesday, November 2, 2004.

Ex. 1 Download and compile the program hello_world_pt.cc with the command

g++ hello_world_pt.cc -o hello -lpthread
Run the program with the command
hello
Read and try to understand the program.

Ex. 2 Modify the previous program such that the parent thread is waiting for all of the others. For each thread in the array you will have to call the function pthread_join with the first argument being the thread (and not a pointer to it), and the second argument being NULL. Once all of the threads have been joined, print a message from the main to say it is done.

Ex. 3 Write a function that takes as an argument the identity of the thread and does the following:

  • locks the mutex,
  • increments the value of the shared variable,
  • prints a message with the value of the shared variable and the identity of the thread,
  • unlocks the mutex.
    • Call this function from the function PrintHello such that it will be called by each of the threads.

    Turn in (optional, 5 extra points): the modified source file for Ex. 3. Only accepted till next Tuesday.