Thank you for the quick reply!
Perls are normally compiled with 64-bit file access, and you might need that for this trick too, because it makes inode numbers wider.
In what way could this affect me? I just have to compare the inode numbers (and device numbers, as you pointed out), as they are returned from stat,isn't it?
Device numbers might not be constant over a reboot.
As I apply the call to stat to both variables in succession, there is no possibility to be interrupted by a reboot.
Ronald Fischer <email@example.com>