Ciao !
ho letto la guida del manuale a proposito della differenze tra le due funzioni. Ecco cosa dice..
Però non capisco quando è meglio usare include_once. Mi fate un esempio molto pratico ?
The include_once() statement includes and evaluates the specified file during the execution of the script. This is a behavior similar to the include() statement, with the only difference being that if the code from a file has already been included, it will not be included again. As the name suggests, it will be included just once.
include_once() may be used in cases where the same file might be included and evaluated more than once during a particular execution of a script, so in this case it may help avoid problems such as function redefinitions, variable value reassignments, etc.