Hi I am setting a session variable inside a function studNameDetails1() while I am trying to retrieve it in a function ViewMark(). These are my two functions but there is no result:

function studNameDetails1()
{
     $_SESSION['ATTsub']=$sub_id = $ID[5];
}
function ViewMark()
{
      echo $_SESSION['ATTsub'];
}

Ben de değerini echo viewMark(), hiçbir değeri yoktur.