Description
mixed 
constant ( string name )
     constant() will return the value of the
     constant indicated by name.
    
     constant() is useful if you need to retrieve
     the value of a constant, but do not know its name.  i.e. It is
     stored in a variable or returned by a function.
    
     
例子 1. constant() example 
<?php
  define("MAXSIZE", 100);
  echo MAXSIZE; echo constant("MAXSIZE"); // same thing as the previous line
  ?>
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     See also define(),
     defined() and the section on Constants.