Removing a non empty directory programmatically in C or C++

Question

How to delete a non empty directory in C or C++? Is there any function? rmdir only deletes empty directory. Please provide a way without using any external library.

Also tell me how to delete a file in C or C++?

Answer 1

You want to write a function (a recursive function is easiest, but can easily run out of stack space on deep directories) that will enumerate the children of a directory. If you find a child that is a directory, you recurse on that. Otherwise, you delete the files inside. When you are done, the directory is empty and you can remove it via the syscall.

To enumerate directories on Unix, you can use opendir(), readdir(), and closedir(). To remove you use rmdir() on an empty directory (i.e. at the end of your function, after deleting the children) and unlink() on a file. Note that on many systems the d_type member in struct dirent is not supported; on these platforms, you will have to use stat() and S_ISDIR(stat.st_mode) to determine if a given path is a directory.

On Windows, you will use FindFirstFile()/FindNextFile() to enumerate, RemoveDirectory() on empty directories, and DeleteFile() to remove files.

Here's an example that might work on Unix (completely untested):

int remove_directory(const char *path) {
   DIR *d = opendir(path);
   size_t path_len = strlen(path);
   int r = -1;

   if (d) {
      struct dirent *p;

      r = 0;
      while (!r && (p=readdir(d))) {
          int r2 = -1;
          char *buf;
          size_t len;

          /* Skip the names "." and ".." as we don't want to recurse on them. */
          if (!strcmp(p->d_name, ".") || !strcmp(p->d_name, ".."))
             continue;

          len = path_len + strlen(p->d_name) + 2; 
          buf = malloc(len);

          if (buf) {
             struct stat statbuf;

             snprintf(buf, len, "%s/%s", path, p->d_name);
             if (!stat(buf, &statbuf)) {
                if (S_ISDIR(statbuf.st_mode))
                   r2 = remove_directory(buf);
                else
                   r2 = unlink(buf);
             }
             free(buf);
          }
          r = r2;
      }
      closedir(d);
   }

   if (!r)
      r = rmdir(path);

   return r;
}