Portable way to check if directory exists [Windows/Linux, C]

I would like to check if a given directory exists. I know how to do this on Windows:

BOOL DirectoryExists(LPCTSTR szPath)
{
  DWORD dwAttrib = GetFileAttributes(szPath);

  return (dwAttrib != INVALID_FILE_ATTRIBUTES && 
         (dwAttrib & FILE_ATTRIBUTE_DIRECTORY));
}

and Linux:

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. */
}

But I need a portable way of doing this .. Is there any way to check if a directory exists no matter what OS Im using? Maybe C standard library way?

I know that I can use preprocessors directives and call those functions on different OSes but thats not the solution Im asking for.

I END UP WITH THIS, AT LEAST FOR NOW:

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

int dirExists(const char *path)
{
    struct stat info;

    if(stat( path, &info ) != 0)
        return 0;
    else if(info.st_mode & S_IFDIR)
        return 1;
    else
        return 0;
}

int main(int argc, char **argv)
{
    const char *path = "./TEST/";
    printf("%d\n", dirExists(path));
    return 0;
}

stat() works on Linux., UNIX and Windows as well:

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

struct stat info;

if( stat( pathname, &info ) != 0 )
    printf( "cannot access %s\n", pathname );
else if( info.st_mode & S_IFDIR )  // S_ISDIR() doesn't exist on my windows 
    printf( "%s is a directory\n", pathname );
else
    printf( "%s is no directory\n", pathname );

With C++17 you can use std::filesystem::is_directory function (https://en.cppreference.com/w/cpp/filesystem/is_directory). It accepts a std::filesystem::path object which can be constructed with a unicode path.

Since I found that the above approved answer lacks some clarity and the op provides an incorrect solution that he/she will use. I therefore hope that the below example will help others. The solution is more or less portable as well.

/******************************************************************************
 * Checks to see if a directory exists. Note: This method only checks the
 * existence of the full path AND if path leaf is a dir.
 *
 * @return  >0 if dir exists AND is a dir,
 *           0 if dir does not exist OR exists but not a dir,
 *          <0 if an error occurred (errno is also set)
 *****************************************************************************/
int dirExists(const char* const path)
{
    struct stat info;

    int statRC = stat( path, &info );
    if( statRC != 0 )
    {
        if (errno == ENOENT)  { return 0; } // something along the path does not exist
        if (errno == ENOTDIR) { return 0; } // something in path prefix is not a dir
        return -1;
    }

    return ( info.st_mode & S_IFDIR ) ? 1 : 0;
}

Use boost::filesystem, that will give you a portable way of doing those kinds of things and abstract away all ugly details for you.

You can use the GTK glib to abstract from OS stuff.

glib provides a g_dir_open() function which should do the trick.

The above examples does not use [_access]1 which can be used for both Windows and Linux. Code sample (Windows) to test with [stat]2, _access() and latest filesystem's [exists]3.

#include <iostream>
#include <Windows.h>
#include <io.h>
#include <filesystem>
#include <vector>
#include <string>

using namespace std;
namespace fs = std::filesystem;
std::vector<std::string> DirPaths
{
  "G:\\My-Shcool-2021-22",
  "\\\\192.168.111.8\\Oaco\\RotData\\VV-VA",
  "\\\\192.168.111.15\\5500\\C-drive\\Oaco\\RotateEarthProject",   "\\\\192.168.111.18\\d$\\Mercurial\\Workspace\\HideMoon\\Win32\\Debug", 
"Z:\\SuperSaver" //mapped network drive; symbolic link
};
/* test if the path is a directory
*/
void TestDirExists ()
{
int erno =-1;
struct stat  info {};
auto ErrorMsg = [&](std::string path) 
{
    _get_errno(&erno);
    if (erno == EACCES)
        cout << "access denied  " << path << endl;
    else if (erno == ENOENT)
        cout << "dir path not found  " << path << endl;
    else if (erno == EINVAL)
        cout << "invalid parameter  " << path << endl;        
};

for (const auto &dp : DirPaths)
{
    erno = -1;
    if (stat(dp.c_str(), &info) != 0)
        ErrorMsg(dp);        
    if (_access(dp.c_str(), 0) != 0)
        ErrorMsg(dp);       
    if (fs::exists(dp)==0)
        ErrorMsg(dp);
    if(erno < 0)
         cout << "#Dir Found: " << dp << endl;
}

} [1]: https://docs.microsoft.com/en-us/cpp/c-runtime-library/reference/access-waccess?view=msvc-170 [2]: https://docs.microsoft.com/en-us/cpp/c-runtime-library/reference/stat-functions?view=msvc-170 [3]: https://en.cppreference.com/w/cpp/filesystem/exists