Because of the 'dot or dot-dot', not 'dot and dot-dot', I construe 'they' as "one or the other, or both if both missing" shall not be returned. You don't synthesize an unnamed or assigned name record for one that isn't present, to relate it to rest of paragraph. This may be off, I can see why you feel the way you do, but it is consistent with the -a and -A descriptions for ls. Both or none only isn't. In a message dated 6/7/2017 11:47:04 A.M. Eastern Daylight Time, stephane.chaze...@gmail.com writes:
2017-06-07 10:58:58 -0400, shwares...@aol.com: > Applications can be written portably and are expected to take into acco unt > a generic file operand is '.' or '..' already; readdir() may or may > not include '.' or '..' values whenever a path crosses a device mount > boundary. It may only have one or the other entries on the media to report; > that is a file system design decision. As worded the implication is if only > one is present, or none, that the other isn't to be synthesized as a > separate dirent, or dirents, or merged with the one that is present as a dirent > extension. [...] The text for readdir() has: http://pubs.opengroup.org/onlinepubs/9699919799.2016edition/functions/readdi r.html SUSv4TC2> If entries for dot or dot-dot exist, one entry shall be SUSv4TC2> returned for dot and one entry shall be returned for SUSv4TC2> dot-dot; otherwise, they shall not be returned. It seems to clearly say that either both entries should be returned or none. My interpretation is that if only one of the two "exists", the other one should be synthetized, though that definition of "exists" is not necessarily clear. If it "exits" in the sense that the "." or ".." path relative to them (as in openat(dirfd(dir), ".")) resolves, then they always exist as we've got a fd on the directory. -- Stephane
