Getting a directory name from a filename

Question

I have a filename (C:\folder\foo.txt) and I need to retrieve the folder name (C:\folder) in C++. In C# I would do something like this:

string folder = new FileInfo("C:\folder\foo.txt").DirectoryName;

Is there a function that can be used in C++ to extract the path from the filename?

score 165 · Answer 1 · answered Jun 18 '10 at 17:11

165

Using Boost.Filesystem:

boost::filesystem::path p("C:\\folder\\foo.txt");
boost::filesystem::path dir = p.parent_path();

answered Jun 18 '10 at 17:11

Khaled Alshaya

94,250
39
176
234

2

`p.remove_filename()` will modify `p` in-place, and [may be implemented more efficiently than `p = p.parent_path()`](http://www.boost.org/doc/libs/1_60_0/libs/filesystem/doc/reference.html#path-remove_filename) – Peter Cordes Feb 09 '16 at 02:14
If you might also deal with directories be aware of the fact that `parent_path()` from `"C:\\folder"` will result in `"C:"`. – Semjon Mössinger May 17 '16 at 12:43
lots of boost gets upgraded to std so also try this .... include .... std::experimental::filesystem::path p("C:\\folder\\foo.txt"); – S Meaden May 26 '17 at 15:44

score 84 · Answer 2 · answered Jun 18 '10 at 17:07

Example from http://www.cplusplus.com/reference/string/string/find_last_of/

// string::find_last_of
#include <iostream>
#include <string>
using namespace std;

void SplitFilename (const string& str)
{
  size_t found;
  cout << "Splitting: " << str << endl;
  found=str.find_last_of("/\\");
  cout << " folder: " << str.substr(0,found) << endl;
  cout << " file: " << str.substr(found+1) << endl;
}

int main ()
{
  string str1 ("/usr/bin/man");
  string str2 ("c:\\windows\\winhelp.exe");

  SplitFilename (str1);
  SplitFilename (str2);

  return 0;
}

This is the best minimal solution here. – plasmacel Oct 29 '18 at 22:47 — plasmacel, Oct 29 '18 at 22:47

score 61 · Answer 3 · edited Nov 03 '18 at 16:31

61

In C++17 there exists a class std::filesystem::path using the method parent_path.

#include <iostream>
#include <filesystem>
namespace fs = std::filesystem;
int main()
{
    for(fs::path p : {"/var/tmp/example.txt", "/", "/var/tmp/."})
        std::cout << "The parent path of " << p
                  << " is " << p.parent_path() << '\n';
}

Possible output:

The parent path of "/var/tmp/example.txt" is "/var/tmp"
The parent path of "/" is ""
The parent path of "/var/tmp/." is "/var/tmp"

edited Nov 03 '18 at 16:31

Zitrax

19,036
20
88
110

answered May 10 '17 at 08:04

Alessandro Jacopson

18,047
15
98
153

4

There also exists a `.remove_filename()` method. – Qqwy Mar 06 '19 at 12:43
2

Thanks, @Qqwy, it also allows to use directory path with that method to get correct and expected results unlike the approach from the answer – IC_ Sep 03 '20 at 06:26
Just be aware that `std::filesystem::path` may use `std::wstring` instead of `std::string` on some platforms, making it difficult to interoperate with normal strings... – David Given Jul 25 '23 at 21:34

score 24 · Accepted Answer · edited Jul 31 '16 at 16:53

24

There is a standard Windows function for this, PathRemoveFileSpec. If you only support Windows 8 and later, it is highly recommended to use PathCchRemoveFileSpec instead. Among other improvements, it is no longer limited to MAX_PATH (260) characters.

edited Jul 31 '16 at 16:53

IInspectable

46,945
8
85
181

answered Jun 18 '10 at 17:12

Andreas Rejbrand

105,602
8
282
384

3

Note that this function is now deprecated. The suggestion from Microsoft is to use [PathCchRemoveFileSpec](https://msdn.microsoft.com/en-us/library/hh707092%28v=vs.85%29.aspx) instead. – default Mar 07 '16 at 17:15
1

@Default: [PathCchRemoveFileSpec](https://msdn.microsoft.com/en-us/library/hh707092.aspx) is only available starting with Windows 8. Since Windows Vista and 7 are still supported, so is [PathRemoveFileSpec](https://msdn.microsoft.com/en-us/library/bb773748.aspx). – IInspectable Jul 31 '16 at 16:51

score 17 · Answer 5 · answered Jan 07 '16 at 22:58

17

Why does it have to be so complicated?

#include <windows.h>

int main(int argc, char** argv)         // argv[0] = C:\dev\test.exe
{
    char *p = strrchr(argv[0], '\\');
    if(p) p[0] = 0;

    printf(argv[0]);                    // argv[0] = C:\dev
}

answered Jan 07 '16 at 22:58

toster-cx

2,287
1
26
32

17

This is not portable. Path separator in linux is '/'. std::filesystem::path is standard and portable. – Rémi Jun 02 '18 at 16:49
Its not robust, but can be made portable. Portability is not always required. I prefer this than ask someone to upgrade to C++17 or install Boost. – brookbot Aug 29 '23 at 21:50

score 7 · Answer 6 · answered Jul 27 '18 at 16:41

 auto p = boost::filesystem::path("test/folder/file.txt");
 std::cout << p.parent_path() << '\n';             // test/folder
 std::cout << p.parent_path().filename() << '\n';  // folder
 std::cout << p.filename() << '\n';                // file.txt

You may need p.parent_path().filename() to get name of parent folder.

score 4 · Answer 7 · answered Jun 18 '10 at 17:11

4

Use boost::filesystem. It will be incorporated into the next standard anyway so you may as well get used to it.

answered Jun 18 '10 at 17:11

Edward Strange

40,307
7
73
125

1

Which standard are you talking about? I know that a lot of things from boost were added to C++ std lib, filesystem will be added too? – McLeary Sep 05 '13 at 12:52
8

"It will be incorporated into the next standard anyway" And it's not – Anton K Jun 22 '15 at 20:39
@AntonK maybe C++ 2017? – Alessandro Jacopson May 10 '17 at 08:04
6

@AlessandroJacopson Cool, it seems included in C++17 - http://en.cppreference.com/w/cpp/filesystem – Anton K May 10 '17 at 17:32

score 3 · Answer 8 · answered Jul 21 '17 at 22:40

3

I'm so surprised no one has mentioned the standard way in Posix

Please use basename / dirname constructs.

man basename

answered Jul 21 '17 at 22:40

Utkarsh Kumar

567
1
5
17

1

The POSIX functions are not without their drawbacks. In particular they may modify the buffer that you pass in, (they really do mean the signature is `basname(char * path)` and not `basename(const char * path)`), and implementations that don't do that appear to have to use a static buffer which makes them thread-unsafe (in principle you could also return dynamically allocated results, but that makes you dependent on `alloc` family functions which is awkward in C++). – dmckee --- ex-moderator kitten Dec 18 '18 at 18:24

score 1 · Answer 9 · answered Jun 18 '10 at 17:39

1

_splitpath is a nice CRT solution.

answered Jun 18 '10 at 17:39

Ofek Shilon

14,734
5
67
101

score -1 · Answer 10 · answered Jun 18 '10 at 17:09

-1

Standard C++ won't do much for you in this regard, since path names are platform-specific. You can manually parse the string (as in glowcoder's answer), use operating system facilities (e.g. http://msdn.microsoft.com/en-us/library/aa364232(v=VS.85).aspx ), or probably the best approach, you can use a third-party filesystem library like boost::filesystem.

answered Jun 18 '10 at 17:09

Cogwheel

22,781
4
49
67

The standard's C++1z is currently attempting to adopt the boost filesystem library as of now making platform-friendliness much less of an issue. It's still in the experimental headers for MSVC, at least. – kayleeFrye_onDeck Jul 08 '17 at 03:18

score -6 · Answer 11 · answered Mar 10 '15 at 02:18

-6

Just use this: ExtractFilePath(your_path_file_name)

answered Mar 10 '15 at 02:18

fxPiotr

1
1

5

I believe this is a Delphi method, not something in C++. – Ian Hunter Nov 05 '15 at 01:29

Getting a directory name from a filename

11 Answers11

Linked

Related