How can I check if a directory exists?

Question

How can I check if a directory exists on Linux in C?

Possible duplicate of [C faster way to check if a directory exists](http://stackoverflow.com/questions/9314586/c-faster-way-to-check-if-a-directory-exists) — patryk.beza, Dec 22 '16 at 11:50
Does this answer your question? [Checking if a directory exists in Unix (system call)](https://stackoverflow.com/questions/3828192/checking-if-a-directory-exists-in-unix-system-call) — MasterHD, Jan 19 '21 at 10:40

score 106 · Accepted Answer · edited May 27 '19 at 13:46

106

You can use opendir() and check if ENOENT == errno on failure:

#include <dirent.h>
#include <errno.h>

DIR* dir = opendir("mydir");
if (dir) {
    /* Directory exists. */
    closedir(dir);
} else if (ENOENT == errno) {
    /* Directory does not exist. */
} else {
    /* opendir() failed for some other reason. */
}

edited May 27 '19 at 13:46

pevik

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answered Sep 20 '12 at 10:38

hmjd

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If the folder does not exists, then how can I create one right away after confirming it does not exists? – Pototo Apr 20 '17 at 18:15
In case you're using Visual Studio, `dirent.h` isn't available, see [this SO post](https://stackoverflow.com/questions/5530933/dirent-h-in-visual-studio-2010-or-2008) for alternatives – gezzahead Apr 09 '18 at 08:49

score 57 · Answer 2 · edited May 27 '19 at 13:48

57

Use the following code to check if a folder exists. It works on both Windows & Linux platforms.

#include <stdio.h>
#include <sys/stat.h>

int main(int argc, char* argv[])
{
    const char* folder;
    //folder = "C:\\Users\\SaMaN\\Desktop\\Ppln";
    folder = "/tmp";
    struct stat sb;

    if (stat(folder, &sb) == 0 && S_ISDIR(sb.st_mode)) {
        printf("YES\n");
    } else {
        printf("NO\n");
    }
}

edited May 27 '19 at 13:48

pevik

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answered Jul 03 '14 at 02:44

Saman

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Are you sure the included headers are sufficient, for Linux at least? – alk May 22 '17 at 19:05
2

S_ISDIR is only for POSIX, not Windows, see [this SO post](https://stackoverflow.com/questions/11238918/s-isreg-macro-undefined) – gezzahead Apr 09 '18 at 08:45

alk · Answer 3 · 2016-10-30T09:22:00.337

19

You might use stat() and pass it the address of a struct stat, then check its member st_mode for having S_IFDIR set.

#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>

...

char d[] = "mydir";

struct stat s = {0};

if (!stat(d, &s))
  printf("'%s' is %sa directory.\n", d, (s.st_mode & S_IFDIR)  : "" ? "not ");
  // (s.st_mode & S_IFDIR) can be replaced with S_ISDIR(s.st_mode)
else
  perror("stat()");

edited Oct 30 '16 at 09:22

answered Sep 20 '12 at 10:44

alk

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I was wondering about `S_IFDIR` vs `S_ISDIR` and found this on the `stat` man page: _"POSIX.1-1990 did not describe the S_IFMT, S_IFSOCK, S_IFLNK, S_IFREG, S_IFBLK, S_IFDIR, S_IFCHR, S_IFIFO, S_ISVTX constants, but instead demanded the use of the macros S_ISDIR(), etc. The S_IF* constants are present in POSIX.1-2001 and later."_ – domsson May 25 '21 at 08:28
`(s.st_mode & S_IFDIR) : "" ? "not "` You seem to have mixed up the `?` and `:` – user16217248 Aug 06 '21 at 22:28

score 11 · Answer 4 · answered Sep 20 '12 at 10:38

The best way is probably trying to open it, using just opendir() for instance.

Note that it's always best to try to use a filesystem resource, and handling any errors occuring because it doesn't exist, rather than just checking and then later trying. There is an obvious race condition in the latter approach.

score 4 · Answer 5 · answered Jan 15 '14 at 22:45

4

According to man(2)stat you can use the S_ISDIR macro on the st_mode field:

bool isdir = S_ISDIR(st.st_mode);

Side note, I would recommend using Boost and/or Qt4 to make cross-platform support easier if your software can be viable on other OSs.

answered Jan 15 '14 at 22:45

TheFriendlyDragon

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2

score 4 · Answer 6 · edited Jun 15 '21 at 14:11

You may also use access in combination with opendir to determine if the directory exists, and, if the name exists, but is not a directory. For example:

#include <sys/stat.h>
#include <dirent.h>
#include <unistd.h>

/* test that dir exists (1 success, -1 does not exist, -2 not dir) */
int
xis_dir (const char *d)
{
    DIR *dirptr;

    if (access ( d, F_OK ) != -1 ) {
        // file exists
        if ((dirptr = opendir (d)) != NULL) {
            closedir (dirptr); /* d exists and is a directory */
        } else {
            return -2; /* d exists but is not a directory */
        }
    } else {
        return -1;     /* d does not exist */
    }

    return 1;
}

nice one, but I would change `int xis_dir (char *d)` to `int xis_dir (const char *d)` as d is not modified. — Danny, Aug 12 '18 at 08:43

How can I check if a directory exists?

6 Answers6

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