Re: std::filesystem::path::append oddity

[Jonathan Wakely <jwakely dot gcc at gmail dot com>]

On Sun, 17 Jun 2018 at 23:01, NightStrike <nightstrike@gmail.com> wrote:
>
> I'm probably missing something abundantly obvious here, but shouldn't these
> two methods of appending be the same according to
> https://en.cppreference.com/w/cpp/filesystem/path/append variants 2 and 3?

https://en.cppreference.com/w/cpp/filesystem/path/append#Parameters
seems pretty clear about the allowed parameters of the (2) and (3)
overloads.

Neither of them can be called with a path object.

>
> #include <filesystem>
> #include <string>
> namespace fs = std::filesystem;
>
> void f() {
>         fs::path p;
>         p /= fs::path("s");  // works

This works because it calls (1).

>         p.append(fs::path("s"));  // doesn't

This is neither a valid argument for the "source" parameter, nor a
pair of iterators.


> }
>
> It appears like clang doesn't support it, either.  The downside here is
> that it prevents being able to do the following:
>
> ifstream if { p.append(...).c_str() };

It's a lot simpler to just do:

ifstream if{p/q};