Get size of a directory on a disk in C++

Question

Following is a code snippet I used to get directory size in c++:

  boost::system::error_code ec;
  boost::filesystem::space_info si =
    boost::filesystem::space(path, ec);
  if (ec.value() == 0) {
    cout << si.capacity - si.available;
  }

But the above snippet seems to be giving the entire disk size instead of a particular directory size on a disk since I passed 2 different directory paths to above but both of them gave the same answer. Can someone help me with finding what's wrong with this or give me another alternative for getting the directory size in c++? TIA!

according to your argumentation addition is broken because `1+3` and `2+2` yield the same result. Please try to explain whats actually wrong — 463035818_is_not_an_ai, Jun 22 '21 at 11:04
You are a aware that `boost::filesystem::space` is for disk size? Please read the manual and check if your assumptions are correct. — Simon Kraemer, Jun 22 '21 at 11:06
`boost::filesystem::space` gives information about the partition containing a path. — interjay, Jun 22 '21 at 11:07
Edited the question now. I need to find the size of a particular directory on a disk. — Doraemon, Jun 22 '21 at 12:41

Erdal Küçük · Answer 1 · 2021-06-22T13:00:05.880

Boost Reference states:

The value of the space_info object is determined as if by using ISO/IEC 9945 statvfs() to obtain an ISO/IEC 9945 struct statvfs.

Opengroup Reference states:

The statvfs() function shall obtain information about the file system containing the file named by path.

man page states:

The function statvfs() returns information about a mounted filesystem. path is the pathname of any file within the mounted filesystem.

Based on your comment:

Have a look at the example of std::filesystem::directory_entry::file_size
Or better: Overview of Filesystem library

If its still not clear:

iterate over a directory
if the entry is of your interest, add the size to the total amount
if entry is another directory, recursively enumerate the size (hint: std::filesystem::recursive_directory_iterator)

statsfs seems to be returning the entire disk space. I want something that gives me the size of a directory alone. Can you please help me with this. — Doraemon, Jun 22 '21 at 12:43

Get size of a directory on a disk in C++

1 Answers1