title: Compilation Error Undefined symbols for architecture x86_64:
body: <p>I have a program that i am trying to compile from my project directory and haven't been able to wrap my head around the following error</p>
  
  <p>My compilation command</p>
  
  <pre><code>g++ grades.cpp -o grades
  </code></pre>
  
  <p>I see the following error </p>
  
  <p><strong>Undefined symbols for architecture x86_64:
    "tbb::task_scheduler_init::initialize(int, unsigned long)", referenced from:
        tbb::task_scheduler_init::task_scheduler_init(int, unsigned long) in grades-9c8d1a.o
    "tbb::task_scheduler_init::terminate()", referenced from:
        tbb::task_scheduler_init::~task_scheduler_init() in grades-9c8d1a.o
  ld: symbol(s) not found for architecture x86_64
  clang: error: linker command failed with exit code 1 (use -v to see invocation)</strong></p>
  
  <p>I am not sure how to debug this error.</p>