std::filesystem (C++17)

TL;DR

A platform-agnostic file system library: path concatenation and normalization, directory creation and traversal, file copying and deletion, permissions and status queries—say goodbye to std::ifstream/std::ofstream and OS APIs.

cpp

#include <filesystem>
namespace fs = std::filesystem;

Core API Cheat Sheet

Operation	Signature	Description
Path class	`std::filesystem::path`	Path construction, concatenation, decomposition (handles cross-platform separators)
Path concatenation	`p / "subdir"`	Joins paths with OS-specific separator
Current path	`fs::current_path`	Gets/sets the working directory
Directory iteration	`fs::directory_iterator`	Iterates over a single-level directory
Recursive iteration	`fs::recursive_directory_iterator`	Recursively iterates over subdirectories
File status	`fs::exists`	Checks if a path exists
File size	`fs::file_size`	Gets file size in bytes
Create directory	`fs::create_directory`	Creates a single directory
Create multi-level directory	`fs::create_directories`	Recursively creates the entire path
Copy file	`fs::copy_file`	Copies a single file
Delete	`fs::remove`	Deletes a file or empty directory
Recursive delete	`fs::remove_all`	Recursively deletes a directory and its contents
Rename	`fs::rename`	Renames or moves a file

Minimal Example

cpp

#include <filesystem>
#include <iostream>

namespace fs = std::filesystem;

int main() {
    // Create directories
    fs::create_directories("sandbox/dir1/dir2");

    // Copy file
    fs::copy_file("source.txt", "sandbox/source.txt");

    // Iterate directory
    for (const auto& entry : fs::directory_iterator("sandbox")) {
        std::cout << entry.path() << '\n';
    }

    // Cleanup
    fs::remove_all("sandbox");
}

Embedded Applicability: Low

Depends on the OS file system abstraction layer (POSIX or Win32); bare-metal environments lack a file system.
Suitable for Embedded Linux (e.g., Buildroot/Yocto platforms) or host-side configuration/logging tools.
Header inclusion overhead is significant; not recommended for resource-constrained devices.
For embedded scenarios requiring a file system (e.g., FAT32 on SD card), consider lightweight alternatives like LittleFS.

Compiler Support

GCC	Clang	MSVC
8	7	19.12

std::filesystem (C++17) ​

TL;DR ​

Header ​

Core API Cheat Sheet ​

Minimal Example ​

Embedded Applicability: Low ​

Compiler Support ​

See Also ​