How do I get the directory that a program is running from?

Question

Is there a platform-agnostic and filesystem-agnostic method to obtain the full path of the directory from where a program is running using C/C++? Not to be confused with the

Answer 1

If you want a standard way without libraries: No. The whole concept of a directory is not included in the standard.

If you agree that some (portable) dependency on a near-standard lib is okay: Use Boost's filesystem library and ask for the initial_path().

IMHO that's as close as you can get, with good karma (Boost is a well-established high quality set of libraries)

Answer 2

For relative paths, here's what I did. I am aware of the age of this question, I simply want to contribute a simpler answer that works in the majority of cases:

Say you have a path like this:

"path/to/file/folder"

For some reason, Linux-built executables made in eclipse work fine with this. However, windows gets very confused if given a path like this to work with!

As stated above there are several ways to get the current path to the executable, but the easiest way I find works a charm in the majority of cases is appending this to the FRONT of your path:

"./path/to/file/folder"

Just adding "./" should get you sorted! :) Then you can start loading from whatever directory you wish, so long as it is with the executable itself.

EDIT: This won't work if you try to launch the executable from code::blocks if that's the development environment being used, as for some reason, code::blocks doesn't load stuff right... :D

EDIT2: Some new things I have found is that if you specify a static path like this one in your code (Assuming Example.data is something you need to load):

"resources/Example.data"

If you then launch your app from the actual directory (or in Windows, you make a shortcut, and set the working dir to your app dir) then it will work like that. Keep this in mind when debugging issues related to missing resource/file paths. (Especially in IDEs that set the wrong working dir when launching a build exe from the IDE)

Answer 3

For Windows system at console you can use system(dir) command. And console gives you information about directory and etc. Read about the dir command at cmd. But for Unix-like systems, I don't know... If this command is run, read bash command. ls does not display directory...

Example:

int main()
{
    system("dir");
    system("pause"); //this wait for Enter-key-press;
    return 0;
}

Answer 4

On POSIX platforms, you can use getcwd().

On Windows, you may use _getcwd(), as use of getcwd() has been deprecated.

For standard libraries, if Boost were standard enough for you, I would have suggested Boost::filesystem, but they seem to have removed path normalization from the proposal. You may have to wait until TR2 becomes readily available for a fully standard solution.

Answer 5

Just my two cents, but doesn't the following code portably work in C++17?

#include <iostream>
#include <filesystem>
namespace fs = std::filesystem;

int main(int argc, char* argv[])
{
    std::cout << "Path is " << fs::path(argv[0]).parent_path() << '\n';
}

Seems to work for me on Linux at least.

Based on the previous idea, I now have:

std::filesystem::path prepend_exe_path(const std::string& filename, const std::string& exe_path = "");

With implementation:

fs::path prepend_exe_path(const std::string& filename, const std::string& exe_path)
{
    static auto exe_parent_path = fs::path(exe_path).parent_path();
    return exe_parent_path / filename;
}

And initialization trick in main():

(void) prepend_exe_path("", argv[0]);

Thanks @Sam Redway for the argv[0] idea. And of course, I understand that C++17 was not around for many years when the OP asked the question.

Answer 6

Works with starting from C++11, using experimental filesystem, and C++14-C++17 as well using official filesystem.

application.h:

#pragma once

//
// https://en.cppreference.com/w/User:D41D8CD98F/feature_testing_macros
//
#ifdef __cpp_lib_filesystem
#include <filesystem>
#else
#include <experimental/filesystem>

namespace std {
    namespace filesystem = experimental::filesystem;
}
#endif

std::filesystem::path getexepath();

application.cpp:

#include "application.h"
#ifdef _WIN32
#include <windows.h>    //GetModuleFileNameW
#else
#include <limits.h>
#include <unistd.h>     //readlink
#endif

std::filesystem::path getexepath()
{
#ifdef _WIN32
    wchar_t path[MAX_PATH] = { 0 };
    GetModuleFileNameW(NULL, path, MAX_PATH);
    return path;
#else
    char result[PATH_MAX];
    ssize_t count = readlink("/proc/self/exe", result, PATH_MAX);
    return std::string(result, (count > 0) ? count : 0);
#endif
}