Question

I am trying to list all the files in a certain directory on a shared drive using the following code:

#include <iostream>
#include <string>

#include "dirent.h"

int main ()
{
    DIR *directoryHandle = opendir("./temp/");
    if (NULL != directoryHandle)
    {
        dirent *entry = readdir(directoryHandle);
        while (NULL != entry)
        {
            //skip directories and select only files (hopefully)
            if ((DT_DIR != entry->d_type) && (DT_REG == entry->d_type || DT_UNKNOWN == entry->d_type))
            {
                std::cout << "Name: " << entry->d_name << " Type:" << std::to_string(entry->d_type) << std::endl;
            }

            //go to next entry
            entry = readdir(directoryHandle);
        }
        closedir(directoryHandle);
    }

    return 0;
}

The problem is that entry->d_type contains DT_UNKNOWN for directories as well as for files in the ./temp/ directory.

Is there any (reliable) linux-specific way to try and read each entry and determine if it’s a file or directory?

The output of cat /etc/SuSE-release is:

SUSE Linux Enterprise Desktop 11 (x86_64) VERSION = 11 PATCHLEVEL = 1

The Linux version is: 2.6.32.59-0.7-default

Still, I expect this code to work on other platforms as well.

Answer 1

Use stat. You’ll get a struct stat with an st_mode field, and macros S_ISDIR/S_ISREG:

isDirectory = S_ISDIR(statBuf.st_mode);
isFile = S_ISREG(statBuf.st_mode);

See man 2 stat. Include sys/stat.h.