std::filesystem (C++17)

In a Nutshell

Platform-independent file system library: path concatenation and normalization, directory creation and traversal, file copy and deletion, permission and status queries -- say goodbye to stat() and opendir().

Header

#include <filesystem>

Core API Quick Reference

Operation	Signature	Description
Path class	class path	Path construction, concatenation, decomposition (cross-platform separator handling)
Path concatenation	path operator/(const path& lhs, const path& rhs)	p / "subdir" / "file.txt"
Current path	path current_path()	Get/set working directory
Directory iteration	class directory_iterator	Iterate a single directory level
Recursive iteration	class recursive_directory_iterator	Recursively iterate subdirectories
File status	bool exists(const path& p)	Check whether a path exists
File size	uintmax_t file_size(const path& p)	Get file size in bytes
Create directory	bool create_directory(const path& p)	Create a single directory
Create directories	bool create_directories(const path& p)	Recursively create the entire path
Copy file	bool copy_file(const path& from, const path& to)	Copy a single file
Remove	bool remove(const path& p)	Remove a file or empty directory
Remove all	uintmax_t remove_all(const path& p)	Recursively remove a directory and its contents
Rename	void rename(const path& old, const path& newp)	Rename or move

Minimal Example

// Standard: C++17
#include <filesystem>
#include <iostream>

namespace fs = std::filesystem;

int main() {
    fs::path p = fs::current_path() / "test.txt";
    std::cout << p << "\n";                      // full path
    std::cout << p.filename() << "\n";           // test.txt
    std::cout << p.extension() << "\n";          // .txt

    fs::create_directories("a/b/c");             // recursive creation
    std::cout << fs::exists("a/b") << "\n";      // true
    fs::remove_all("a");                         // recursive removal
}

Embedded Applicability: Low

• Depends on OS file system abstraction layers (POSIX or Win32); bare-metal environments have no 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 extremely resource-constrained devices
• For embedded scenarios that require a file system (e.g., FAT32 on SD card), consider lightweight alternatives such as LittleFS

Compiler Support

GCC	Clang	MSVC
8	7	19.12

See Also

• cppreference: std::filesystem

---

Some content adapted from cppreference.com under CC-BY-SA 4.0 license