CODEWITHSUNDEEP
c++boost-filesystemstd-filesystem
Curious
Curious

Reputation: 128

Why do std::filesystem::path::compare() and boost::filesystem::path::compare() differ?

Given the following code:

  fs::path p{ "a/b/" };
  fs::path q{ "a/b/." };  
  assert(p == q);

[Note the extra dot at the end of the string defining q.]

With the above, boost::filesystem accepts p == q as true, but gcc's and llvm's implementation of std::filesystem say it is false.

Why the discrepancy between boost and std?

P.S. In previous versions of this question, I erroneously thought that the paths were supposed to be normalized before comparison. That is not the case. Even so, the discrepancy between boost and std is still a mystery to me.

Upvotes: 3

Views: 742

Answers (1)

Zuodian Hu
Zuodian Hu

Reputation: 1009

The short answer is that . on Unix is an actual filesystem node link, and that matters sometimes. See this stack overflow answer.

EDIT

However, I can't presume to know the Standard Committee's intentions with regard to filesystem library behavior, nor do I think it's reasonable for the library to know that much about Unix symlink behavior. In short, this may or may not just be a quirk of the Standard wording vs Boost's opinion of how things should work.

Upvotes: 1

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