i have doubt on this particular problem : Global variabe initiation. i got this code and has global variable named conditional_random here :

function hello_testing() {
  global $conditional_random;
  if (isset($conditional_random)) {
      echo "foo is inside";  
  }

}

As it's name, the global variable (conditional_random) can be or not initiate before the hello_testing function been called.

So, what happen to my validation via isset() when $conditional_random is not initiate before the hello_testing function ? will it failed to check or it will always be true cause by the 'global' ?