How can I get a list of files in a directory using C or C++?

Question

How can I determine the list of files in a directory from inside my C or C++ code?

I'm not allowed to execute the 'ls' command and parse the results from within my program.

Answer 1

Try boost for x-platform method

http://www.boost.org/doc/libs/1_38_0/libs/filesystem/doc/index.htm

or just use your OS specific file stuff.

Answer 2

Unfortunately the C++ standard does not define a standard way of working with files and folders in this way.

Since there is no cross platform way, the best cross platform way is to use a library such as the boost filesystem module.

Cross platform boost method:

The following function, given a directory path and a file name, recursively searches the directory and its sub-directories for the file name, returning a bool, and if successful, the path to the file that was found.

bool find_file( const path & dir_path,         // in this directory,
                const std::string & file_name, // search for this name,
                path & path_found )            // placing path here if found
{
  if ( !exists( dir_path ) ) return false;
  directory_iterator end_itr; // default construction yields past-the-end
  for ( directory_iterator itr( dir_path );
        itr != end_itr;
        ++itr )
  {
    if ( is_directory(itr->status()) )
    {
      if ( find_file( itr->path(), file_name, path_found ) ) return true;
    }
    else if ( itr->leaf() == file_name ) // see below
    {
      path_found = itr->path();
      return true;
    }
  }
  return false;
}

Source from the boost page mentioned above.

---

For Unix/Linux based systems:

You can use opendir / readdir / closedir.

Sample code which searches a directory for entry ``name'' is:

   len = strlen(name);
   dirp = opendir(".");
   while ((dp = readdir(dirp)) != NULL)
           if (dp->d_namlen == len && !strcmp(dp->d_name, name)) {
                   (void)closedir(dirp);
                   return FOUND;
           }
   (void)closedir(dirp);
   return NOT_FOUND;

Source code from the above man pages.

---

For a windows based systems:

you can use the Win32 API FindFirstFile / FindNextFile / FindClose functions.

The following C++ example shows you a minimal use of FindFirstFile.

#include <windows.h>
#include <tchar.h>
#include <stdio.h>

void _tmain(int argc, TCHAR *argv[])
{
   WIN32_FIND_DATA FindFileData;
   HANDLE hFind;

   if( argc != 2 )
   {
      _tprintf(TEXT("Usage: %s [target_file]\n"), argv[0]);
      return;
   }

   _tprintf (TEXT("Target file is %s\n"), argv[1]);
   hFind = FindFirstFile(argv[1], &FindFileData);
   if (hFind == INVALID_HANDLE_VALUE) 
   {
      printf ("FindFirstFile failed (%d)\n", GetLastError());
      return;
   } 
   else 
   {
      _tprintf (TEXT("The first file found is %s\n"), 
                FindFileData.cFileName);
      FindClose(hFind);
   }
}

Source code from the above msdn pages.

Answer 3

In small and simple tasks I do not use boost, I use dirent.h which is also available for windows:

DIR *dir;
struct dirent *ent;
 dir = opendir ("c:\\src\\");
if (dir != NULL) {

  /* print all the files and directories within directory */
  while ((ent = readdir (dir)) != NULL) {
    printf ("%s\n", ent->d_name);
  }
  closedir (dir);
} else {
  /* could not open directory */
  perror ("");
  return EXIT_FAILURE;
}

It is just a small header file and does most of the simple stuff you need without using a big template-based approach like boost(no offence, I like boost!). I googled and found some links here The author of the windows compatibility layer is Toni Ronkko. In unix it is a standard-header

Answer 4

This is a duplicate of 609236