Quickstart

Quickstart: Your First MSG File in C++

This guide creates a complete, runnable example — composing an email, saving it as an MSG file, loading it back, and converting it to EML — using only the standard C++ library and Aspose.Email FOSS for C++.

Prerequisites

Requirement	Detail
Compiler	C++17 or later (GCC 9+, Clang 10+, MSVC 2019+)
Build system	CMake 3.26 or later
Library	Cloned from GitHub (see Installation)
Dependencies	None

Step 1: Set Up Your CMakeLists.txt

cmake_minimum_required(VERSION 3.26)
project(email_quickstart)

add_subdirectory(Aspose.Email-FOSS-for-Cpp)

add_executable(quickstart main.cpp)
target_link_libraries(quickstart PRIVATE AsposeEmailFoss::AsposeEmailFoss)
set_target_properties(quickstart PROPERTIES CXX_STANDARD 17)

Step 2: Create and Save an MSG File

Create a new MSG file with subject, body, sender, a recipient, and an attachment:

#include <fstream>
#include <vector>
#include "aspose/email/foss/msg/mapi_message.hpp"

int main()
{
    // Compose the message
    auto message = aspose::email::foss::msg::mapi_message::create(
        "Hello from Aspose.Email FOSS",
        "This message was created programmatically — no Outlook required.");

    message.set_sender_name("Alice");
    message.set_sender_email_address("alice@example.com");
    message.add_recipient("bob@example.com", "Bob");
    message.add_attachment(
        "readme.txt",
        std::vector<std::uint8_t>{'H', 'e', 'l', 'l', 'o', '\n'},
        "text/plain");

    // Save to MSG file
    std::ofstream out("hello.msg", std::ios::binary);
    message.save(out);

    return 0;
}

Build and run:

cmake -B build -DCMAKE_BUILD_TYPE=Release
cmake --build build
./build/quickstart

The file hello.msg is created in the working directory. Open it in Outlook to verify, or continue to step 3 to read it back programmatically.

Step 3: Read the MSG File Back

Load the file you just created and print its properties:

#include <fstream>
#include <iostream>
#include "aspose/email/foss/msg/mapi_message.hpp"

int main()
{
    std::ifstream input("hello.msg", std::ios::binary);
    const auto message = aspose::email::foss::msg::mapi_message::from_stream(input);

    std::cout << "Subject:     " << message.subject() << '\n';
    std::cout << "From:        " << message.sender_name()
              << " <" << message.sender_email_address() << ">\n";
    std::cout << "Body:        " << message.body() << '\n';
    std::cout << "Recipients:  " << message.recipients().size() << '\n';
    std::cout << "Attachments: " << message.attachments().size() << '\n';

    for (const auto& a : message.attachments())
        std::cout << "  - " << a.filename << " (" << a.data.size() << " bytes)\n";

    return 0;
}

Expected output:

Subject:     Hello from Aspose.Email FOSS
From:        Alice <alice@example.com>
Body:        This message was created programmatically — no Outlook required.
Recipients:  1
Attachments: 1
  - readme.txt (6 bytes)

Step 4: Convert to EML

Convert the MSG file to RFC 5322 / MIME format with save_to_eml():

#include <filesystem>
#include <iostream>
#include "aspose/email/foss/msg/mapi_message.hpp"

int main()
{
    const auto message = aspose::email::foss::msg::mapi_message::from_file(
        std::filesystem::path("hello.msg"));

    message.save_to_eml(std::filesystem::path("hello.eml"));
    std::cout << "Saved hello.eml\n";

    return 0;
}

Subject, body, sender, recipients, and the attachment are all preserved in the EML output.

Next Steps

Installation — full CMake project setup and supported platforms
Features — complete feature reference with C++ examples
Developer Guide — MSG, EML, CFB, and MAPI property walkthroughs
FAQ — licensing, format support, known limitations