Dotenv for C++

A lightweight C++ library for loading and parsing environment variables from a .env file with JavaScript-like variable expansion.

📝 About this repository

• This project is owned by @harshfeudal.
• A header-only C++ library perfect for managing configuration variables, such as tokens for a Discord bot using D++. Use with .gitignore to keep your .env file secure.

🚨 Usage

1. Download the dotenv folder containing dotenv.h.
2. Include and use it in your project like this:

main.cpp

#include <dotenv/dotenv.h>
#include <iostream>

int main() {
    Dotenv env;
    
    // Load your .env file
    if (!env.load(".env")) {
        std::cerr << "Failed to load .env file" << std::endl;
        return 1;
    }

    // Read your .env variable
    std::string my_var = env.get("MY_VAR");
    std::cout << "The variable is: " << my_var << std::endl;

    // Get with default value
    std::string missing_var = env.get("MISSING", "default value");
    std::cout << "Missing variable: " << missing_var << std::endl;

    return 0;
}

Note: If you would like to use the non-OOP version, please include only dotenv-alt.h. It provides a set of functions instead of a class-based interface. This can be useful for simpler use cases or when you prefer a procedural approach.

✨ Library features

1. Formatted Strings: Supports escape sequences in double-quoted values:

SENTENCE="\n\"Hello World\"\n\t- Hello 2025 -"

Outputs:

The sentence is:
"Hello World"
    - Hello 2025 -

2. Comments: Ignores content after # when not in quotes:

TOKEN="WW91ckRpc2NvcmRCb3RUb2tlbg=="    # Your Discord bot token

3. Header-Only: Just include dotenv.h - no additional linking required!

4. Variable Expansion: JavaScript-like variable substitution:

• $KEY or ${KEY} expands to the value of KEY
• \$KEY escapes the expansion
• ${KEY:-default} uses "default" if KEY is unset

Example:

HOST=localhost
URL=$HOST:8080
SAFE=\$HOST
FALLBACK=${UNSET:-default}

5. Quote Support: Supports single ('), double ("), and backtick (`) quotes. Only double-quoted values process escapes.

6. Empty Values: Handles empty variables:

👷 Support Platform

• Microsoft Windows 10/11 x64/x86
• Visual Studio platform x64/x86
• C++17 ISO/IEC 14882

💎 Contribution and Pull Request

Contributions are welcome! Please:

• Test your changes thoroughly
• Submit a pull request

Don't worry about mistakes - we'll work together to refine it

📚 Download

Get the latest version here.

🤝 Support me

Please leave a star if you like it. Thank you!