php - Making a directory based on username? -

i trying create directory mkdir code. when use code :

mkdir("test"); 

then, "test" directory created. when try this

mkdir($_session['username']); 

then, got error saying

warning: mkdir(): open_basedir restriction in effect. file() not within allowed path(s)

what mean? tried

$path = $_session['username']; mkdir($path); 

and

mkdir("".$_session['username'].""); 

but gives me same error message. supposed do?

make sure prefix folder name full path want create folders. ie, if trying create folders under /tmp/users might use code like:

mkdir('/tmp/users/' . $_session['username']); 

you need make sure have configured php allow access path. see open_basedir ini directive: http://php.net/manual/en/ini.core.php#ini.open-basedir