That is important for the purposes of building paths through concatenation to know that sys_get_temp_dir does not include a path separator at the end.
So, sys_get_temp_dir() will return whatever your temp dir is set to, by default:
/tmp
If you attempted to concatenate another dir name temp and use the following:
mkdir(sys_get_temp_dir() . 'some_dir');
That would actually attempt to generate:
/tmpsome_dir
It would likely result in a permission error unless you are running a php script as a super user.
Instead you would want to do:
mkdir( sys_get_temp_dir() . DIRECTORY_SEPARATOR. 'some_dir' );
which would create:
/tmp/some_dir
I don't know if Windows or other platforms include a directory separator at the end. So if you are writing something a bit more general you may want to check for the path separator at the end and if it is not there append it.
