Get the absolute path from std::filesystem::path c++

Question

I have this piece of code

auto path = std::filesystem::path("/root/home/../opt/.");

I had tried std::filesystem::absolute() but then realized it is for something else than the reasult I want

My question is how can i convert that relative path to the absolute path so that the reasult will be "/root/opt/".

I am using c++17 on Debian g++-9

You want the canonical path ([link](https://en.cppreference.com/w/cpp/filesystem/canonical)). — f9c69e9781fa194211448473495534, Jul 04 '20 at 11:45

score 13 · Accepted Answer · answered Jul 04 '20 at 11:52

13

Use std::filesystem::canonical to turn the path into an absolute path with all .. removed (reference):

auto path = std::filesystem::canonical("/root/home/../opt/.");

Gives you:

"/root/opt"

answered Jul 04 '20 at 11:52

score 7 · Answer 2 · answered Jul 04 '20 at 12:00

7

You can also use from this function.

 std::cout << std::filesystem::path("/root/home/../opt/.").lexically_normal()    << std::endl;

answered Jul 04 '20 at 12:00

Farhad Sarvari

6

It's worth noting: unlike the other answer (`canonical`), the `lexically_normal` method will not attempt to resolve symlinks, and in fact won't do any file system operations at all. It's just a string manipulation method, hence the name. Depending on the situation, this may or may not be what you want. – Arthur Tacca Jul 04 '20 at 12:04

2 Answers2