Reading the documentation on the function is always a good place to start:
fr.php.net/manual/fr/function.move-uploaded-file.php
www.php.net/move_uploaded_file
Si filename n'est pas valide, rien ne se passe, et move_uploaded_file() retournera FALSE.
Si filename est un fichier téléchargé, mais que pour une raison quelconque, il ne peut être déplacé, rien ne se passe, et move_uploaded_file() retourne FALSE. De plus, une alerte sera affichée.
If filename is not a valid upload file, then no action will occur, and move_uploaded_file() will return FALSE.
If filename is a valid upload file, but cannot be moved for some reason, no action will occur, and move_uploaded_file() will return FALSE. Additionally, a warning will be issued.
The warning message indicates that your Apache process does not have permission to access/write to your destination folder. Use the Linux command chmod
to adjust the folder's permission settings to allow apache access.