   #PHP Manual Miscellaneous functions die exit

   PHP Manual
   Prev  Next
   ______________________________________________________________________

                                     eval

   (PHP 3, PHP 4 )
   eval -- Evaluate a string as PHP code

Description

   mixed eval ( string code_str)

   eval() evaluates the string given in code_str as PHP code. Among other
   things, this can be useful for storing code in a database text field
   for later execution.

   There are some factors to keep in mind when using eval(). Remember
   that the string passed must be valid PHP code, including things like
   terminating statements with a semicolon so the parser doesn't die on
   the line after the eval(), and properly escaping things in code_str.

   Also remember that variables given values under eval() will retain
   these values in the main script afterwards.

   A return statement will terminate the evaluation of the string
   immediately. In PHP 4, eval() returns NULL unless return is called in
   the evaluated code, in which case the value passed to return is
   returned. In PHP 3, eval() does not return a value.

   Example 1. eval() example - simple text merge
   <?php
   $string = 'cup';
   $name = 'coffee';
   $str = 'This is a $string with my $name in it.';
   echo $str. "\n";
   eval("\$str = \"$str\";");
   echo $str. "\n";
   ?>

   The above example will show:
This is a $string with my $name in it.
This is a cup with my coffee in it.

     Tip: As with anything that outputs its result directly to the
     browser, you can use the output-control functions to capture the
     output of this function, and save it in a string (for example).
   ______________________________________________________________________

   Prev Home Next
   die   Up  exit
