Description
string 
ini_set ( string varname, string newvalue )
     Sets the value of the given configuration option. Returns the old
     value on success, FALSE on failure. The configuration option
     will keep this new value during the script's execution, and will
     be restored at the script's ending.
    
     Not all the available options can be changed using
     ini_set(). There is a list of all available options in
     the appendix.
    
     See also: get_cfg_var(),
     ini_get(),
     ini_get_all(),
     ini_restore()  and
     How to change configuration
     settings