C++ Library - <filesystem>

The <filesystem> header in C++, provides a set of functions for performing operations on the file system, such as manipulating paths, copying or deleting files and checking file status.

The <filesystem> library may be unavailable if a hierarchical file system is not accessible to the implementation, or if it does not provide the necessary capabilities. Some features may not be available if they are not supported by the underlying file system, such as FAT(File Allocation Table).

Including <filesystem> Header

To include the <filesystem> header in your C++ program, you can use the following syntax.

#include <filesystem>

Functions of <filesystem> Header

Below is list of all functions from <filesystem> header.

Path Manipulation Functions

This path manipulation functions operate on file paths to compose, convert or resolve them.

Path Manipulation Example

In the following example we are going to use, exists() checking whether the specified path (filePath) refers to an existing file system object.

#include <iostream>
#include <filesystem>
int main() {
    std::filesystem::path filePath{"example.txt"};

    if (std::filesystem::exists(filePath)) {
        std::cout << "The file exists." << std::endl;
    } else {
        std::cout << "The file does not exist." << std::endl;
    }
    return 0;
}

Output

If we run the above code it will generate the following output

The file does not exist.

File types

The <filesystem> library provides several functions that determine the type of file or directory specified by a path. These functions are used for understanding the characteristics of files and implementing logic based on file types.

Checking the Specified Path

In the following example we are going to use, is_directory to check if the specified path (dirPath) refers to a directory.

#include <iostream>
#include <filesystem>
int main() {
    std::filesystem::path dirPath{"my_directory"};

    if (std::filesystem::is_directory(dirPath)) {
        std::cout << "This path refers to a directory." << std::endl;
    } else {
        std::cout << "This path does not refer to a directory." << std::endl;
    }
    return 0;
}

Output

If we run the above code it will generate the following output

This path does not refer to a directory.