The point of mktemp is to use the right location on the current system, which may not be /tmp. If you're going to enforce that tmpdir must be /tmp, you might as

The point of mktemp is to use the right location on the current system, which may not be /tmp. If you're going to enforce that tmpdir must be /tmp, you might as well not bother with mktemp and just directly create a file or directory in /tmp.