std::filesystem::is_empty(3)

🌸 std::filesystem::is_empty(3) — C++ Standard Libary 🌸

🎀 NAME 🎀

std::filesystem::is_empty — std::filesystem::is_empty. That's the whole NAME, bestie. 💅

✨ Synopsis ✨

Defined in header <filesystem>.

bool is_empty( const std::filesystem::path& p );

(1) (since C++17)

bool is_empty( const std::filesystem::path& p, std::error_code& ec );

(2) (since C++17)

Checks whether the given path refers to an empty file or directory. 🫶

🌟 Parameters 🌟

• p — path to examine. 👀
• ec — error code to modify in case of error. 🛠️

💖 Return value 💖

true if the path indicated by p refers to an empty file or directory, and false otherwise. The non-throwing overload returns false if an error occurs. ✨

😭 Exceptions 😭

Any overload not marked noexcept may throw std::bad_alloc if memory allocation fails. No cap, that's literally the rule. 💀

1. Throws std::filesystem::filesystem_error on underlying OS API errors, constructed with p as the first path argument and the OS error code as the error code argument. 🚨
2. Sets a std::error_code& parameter to the OS API error code if an OS API call fails, and executes ec.clear() if no errors occur. 🌈

🧚 Example 🧚

// Run this code

#include <cstdio>
#include <filesystem>
#include <fstream>
#include <iostream>

int main()
{
    namespace fs = std::filesystem;

    const fs::path tmp_dir{fs::temp_directory_path()};
    std::cout << std::boolalpha
              << "Temp dir: " << tmp_dir << '\n'
              << "is_empty(): " << fs::is_empty(tmp_dir) << '\n';

    const fs::path tmp_name{tmp_dir / std::tmpnam(nullptr)};
    std::cout << "Temp file: " << tmp_name << '\n';

    std::ofstream file{tmp_name.string()};
    std::cout << "is_empty(): " << fs::is_empty(tmp_name) << '\n';
    file << "cppreference.com";
    file.flush();
    std::cout << "is_empty(): " << fs::is_empty(tmp_name) << '\n'
              << "file_size(): " << fs::file_size(tmp_name) << '\n';
    file.close();
    fs::remove(tmp_name);
}

🌈 Possible output: 🌈

Temp dir: "/tmp"
is_empty(): false
Temp file: "/tmp/fileCqd9DM"
is_empty(): true
is_empty(): false
file_size(): 16

👑 Defect reports 👑

The following behavior-changing defect reports were applied retroactively to previously published C++ standards. 📚

• DR: LWG 3013 — Applied to: C++17. Behavior as published: error_code overload marked noexcept but can allocate memory. Correct behavior: noexcept removed. 💀

💜 See also 💜

• status — determines file attributes. (C++17) (function) 🌟
• symlink_status — determines file attributes, checking the symlink target. (C++17) (function) 🦋
• exists — checks whether path refers to existing file system object. (C++17) (function) ✨

okay that's the whole page, bestie! Source/version: http://cppreference.com; date: 2024.06.10; footer: std::filesystem::is_empty(3). Byeee, go check if your folders are empty 💖✨