CODEWITHSUNDEEP
c++boostpathfilesystems
user1598585
user1598585

Reputation:

Get absolute path with boost::filesystem::path

My current working directory is located at /home/myuser/program, I created a boost::filesystem::path object pointing to it. I appended /../somedir so it becomes /home/myuser/program/../somedir. But I need to get its resolved absolute path, which would be /home/myuser/somedir.

I have been trying for long time and I do not find any method in their reference to do this. There is a method called make_absolute, which seems to be supposed to do what I expect, but I have to give it a “root” path argument. Which should it be? do I really need to do this to get the real absolute path? Is there any other way?

Upvotes: 32

Views: 48710

Answers (5)

wjx0912
wjx0912

Reputation: 19

// input: d:\\tmp\\\\a/../VsDebugConsole.png
// output: d:\\tmp\\VsDebugConsole.png
static std::wstring fix_path(std::wstring path)
{
    //boost::replace_all(path, L"\\\\", L"\\");
    //boost::replace_all(path, L"//", L"/");
    boost::filesystem::path bpath(path);
    bpath = boost::filesystem::system_complete(bpath);

    return bpath.wstring();
}

Upvotes: 0

Daniel
Daniel

Reputation: 1447

Update, since this still appears to be Google's top hit concerning absolute paths:

As of Boost 1.57, some of the previously suggested functions have since been removed.

The solution that worked for me was

boost::filesystem::path canonicalPath = boost::filesystem::canonical(previousPath, relativeTo);

(using the free-standing method canonical(), defined in boost/filesystem/operations.hpp, which is automatically included via boost/filesystem.hpp)

Important: calling canonical on a path that does not exist (e.g., you want to create a file) will throw an exception. In that case, your next best bet is probably boost::filesystem::absolute(). It will also work for non-existing paths, but won't get rid of dots in the middle of the path (as in a/b/c/../../d.txt). Note: Make sure relativeTo refers to a directory, calling parent_path() on paths referring to files (e.g. the opened file that contained a directory or file path relative to itself).

Upvotes: 14

Rob Kennedy
Rob Kennedy

Reputation: 163247

You say you want an absolute path, but your example shows that you already have an absolute path. The process of removing the .. components of a path is known as canonicalization. For that, you should call canonical. It happens to also perform the task of absolute, so you don't need to call absolute or make_absolute first. The make_absolute function requires a base path; you can pass it current_path() if you don't have anything better.

Upvotes: 25

Nicol Bolas
Nicol Bolas

Reputation: 473222

I have to give it a “root” path argument.

Check the docs: you don't have to give it anything; it has a default second parameter. Namely, the current directory.

Relative paths are relative to some directory. Thus, when making a path absolute, you need to know what it should be absolute relative to. That's the "root path": the directory it is relative to.

Upvotes: 0

Mr. Llama
Mr. Llama

Reputation: 20889

The documentation shows that the make_absolute has an optional second parameter that defaults to your current path:

path absolute(const path& p, const path& base=current_path());

Try it without the second parameter and see if it returns the results you're looking for.

Upvotes: 1

Related Questions