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. To mix
HTML output and PHP code you can use a closing PHP tag to leave PHP mode.
Also remember that variables given values under eval() will retain these values in the main script afterwards.
The code string to be evaluated.
code_str does not have to contain PHP Opening tags.
A return statement will immediately terminate the evaluation of the string .
As of PHP 4, eval() returns NULL unless return is called in the evaluated code, in which case the value passed to return is returned. In case of a parse error in the evaluated code, eval() returns FALSE.
In PHP 3, eval() does not return a value.
Note: Because this is a language construct and not a function, it cannot be called using variable functions
Note: In case of a fatal error in the evaluated code, the whole script exits.