dotenv is a minimalistic, header-only C++ library that brings .env-style environment variable management to your C++ projects, inspired by the simplicity of dotenv in other languages. It’s designed to load, set, and retrieve environment variables, letting you keep configurations out of your code and in a clean, readable .env file. Best of all? No dependencies. It just works.

• Loads environment variables from a .env file in KEY=VALUE format.
• Provides functions to retrieve variables with an optional default value.
• Allows setting environment variables programmatically in the current process.
• Works across platforms (Windows, Linux, macOS).

Since dotenv is a header-only library, there's no need to compile or link any external files. Simply download or clone this repository and include dotenv.h in your project.

To use dotenv, include the dotenv.h header file in your C++ project. Here’s a quick example.

Create a .env file with some environment variables. For example:

# .env
DB_HOST=127.0.0.1
DB_USER=admin
DB_PASSWORD=secret

In your C++ code, include dotenv.h and use dotenv to load and retrieve environment variables.

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

int main() {
    dotenv env(".env");  // Load variables from .env file

    // Retrieve variables with default values if they are not set
    std::string db_host = env.get("DB_HOST", "localhost");
    std::string db_user = env.get("DB_USER", "root");
    std::string db_password = env.get("DB_PASSWORD", "");

    std::cout << "Database Host: " << db_host << std::endl;
    std::cout << "Database User: " << db_user << std::endl;
    std::cout << "Database Password: " << db_password << std::endl;

    // Set a new environment variable within this process
    env.set("NEW_VAR", "new_value");
    std::cout << "New Variable: " << env.get("NEW_VAR") << std::endl;

    return 0;
}

Since dotenv is a header-only library, you don’t need to link any additional files. Compile your program as usual:

g++ main.cpp -o main

1. Load from .env: dotenv env(".env"); loads environment variables from the specified .env file.
2. Retrieve with Defaults: env.get("DB_HOST", "localhost"); retrieves the DB_HOST variable, or returns "localhost" if DB_HOST is not set.
3. Set New Variables: env.set("NEW_VAR", "new_value"); sets a new variable within the current process.

dotenv uses _putenv_s on Windows and setenv on Unix-like systems to set environment variables. This ensures cross-platform compatibility, allowing you to use the same code on Windows, macOS, and Linux.

For information on setting up and running tests for dotenv, please refer to the Testing Instructions.

This project is licensed under the MIT License - see the LICENSE file for details.

Contributions are welcome! Feel free to fork this repository and submit a pull request for any bug fixes or new features.