One note which I would add to this, is that both of these functions employ the stat() function "under the hood" - Information returned from this call is cached such that subsequent calls to stat, lstat or the -X file tests employing the special filehandle consisting of a solitary underline character (_) can employ this cached information rather than again calling the underlying stat() function.

This behaviour is documented in perlfunc.

 

perl -le 'print+unpack"N",pack"B32","00000000000000000000001001101011"'