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

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

#include 
#include 
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.