title: Safe values to be used as key in shmget
body: <p>I'm using shmget for sharing data between processes of my project on Linux.</p>
  
  <pre><code>int shmget(key_t key, size_t size, int shmflg);
  </code></pre>
  
  <p>However, any other programs can call to shmget too, and thus it may lead to key conflict (because I use a constant as the key to call shmget, I must use a constant instead of a generated key because the lateral processes are built and run separately).</p>
  
  <p>What should be the safe values to be used as key in shmget?</p>