Send Email using Gmail in Visual C++

In previous section, I introduced how to send email over SSL connection. In this section, I will introduce how to use your Gmail account to send email in Visual C++.

Introduction

Gmail SMTP server address is smtp.gmail.com. It requires implicit SSL or explicit SSL (TLS) connection, and you should use your Gmail email address as the user name for ESMTP authentication.

Server Port SSL/TLS
smtp.gmail.com 25, 587 TLS
smtp.gmail.com 465 SSL

Gmial App Password

To help keep your account secure, starting May 30, 2022, ​​Google will no longer support the use of third-party apps or devices which ask you to sign in to your Google Account using only your username and password.

Therefore, you should sign in using App Passwords. An App Password is a 16-digit passcode that gives a less secure app or device permission to access your Google Account. App Passwords can only be used with accounts that have 2-Step Verification turned on. You need to use App Password instead of the user password for user authentication.

Another solution is Gmail OAUH, please see Gmail SMTP OAUTH section.

Note

Remarks: All of samples in this section are based on first section: A simple Visual C++ project. To compile and run the following example codes successfully, please click here to learn how to create the test project and add reference of EASendMail to your project.

[Visual C++ Example - Send email using Gmail account over Implicit SSL connection on 465 port]

The following example codes demonstrate how to send email using Gmail account.

Note

To get the full sample projects, please refer to Samples section.

#include "stdafx.h"
#include <tchar.h>
#include <Windows.h>

#include "EASendMailObj.tlh"
using namespace EASendMailObjLib;

const int ConnectNormal = 0;
const int ConnectSSLAuto = 1;
const int ConnectSTARTTLS = 2;
const int ConnectDirectSSL = 3;
const int ConnectTryTLS = 4;

int _tmain(int argc, _TCHAR* argv[])
{
    ::CoInitialize(NULL);

    IMailPtr oSmtp = NULL;
    oSmtp.CreateInstance(__uuidof(EASendMailObjLib::Mail));
    oSmtp->LicenseCode = _T("TryIt");

    // Set your gmail email address
    oSmtp->FromAddr = _T("gmailid@gmail.com");
    // Add recipient email address
    oSmtp->AddRecipientEx(_T("support@emailarchitect.net"), 0);

    // Set email subject
    oSmtp->Subject = _T("simple email from Visual C++ with gmail account");
    // Set email body
    oSmtp->BodyText = _T("this is a test email sent from Visual C++ project with Gmail");

    // Gmail SMTP server address
    oSmtp->ServerAddr = _T("smtp.gmail.com");

    // Gmail user authentication should use your
    // Gmail email address as the user name.
    // For example: your email is "gmailid@gmail.com", then the user should be "gmailid@gmail.com"
    oSmtp->UserName = _T("gmailid@gmail.com");

    // Create app password in Google account
    // https://support.google.com/accounts/answer/185833?hl=en
    oSmtp->Password = _T("your app password");

    // Use SSL 465 port,
    oSmtp->ServerPort = 465;

    // detect SSL/TLS automatically
    oSmtp->ConnectType = ConnectSSLAuto;

    _tprintf(_T("Start to send email via gmail account ...\r\n"));

    if(oSmtp->SendMail() == 0)
    {
        _tprintf(_T("email was sent successfully!\r\n"));
    }
    else
    {
        _tprintf(_T("failed to send email with the following error: %s\r\n"),
            (const TCHAR*)oSmtp->GetLastErrDescription());
    }

    return 0;
}

[Visual C++ Example - Send email using Gmail account over TLS connection on 587 port]

The following example codes demonstrate how to send email using Gmail account. To get the full samples of EASendMail, please refer to Samples section.

#include "stdafx.h"
#include <tchar.h>
#include <Windows.h>

#include "EASendMailObj.tlh"
using namespace EASendMailObjLib;

const int ConnectNormal = 0;
const int ConnectSSLAuto = 1;
const int ConnectSTARTTLS = 2;
const int ConnectDirectSSL = 3;
const int ConnectTryTLS = 4;

int _tmain(int argc, _TCHAR* argv[])
{
    ::CoInitialize(NULL);

    IMailPtr oSmtp = NULL;
    oSmtp.CreateInstance(__uuidof(EASendMailObjLib::Mail));
    oSmtp->LicenseCode = _T("TryIt");

    // Set your gmail email address
    oSmtp->FromAddr = _T("gmailid@gmail.com");
    // Add recipient email address
    oSmtp->AddRecipientEx(_T("support@emailarchitect.net"), 0);

    // Set email subject
    oSmtp->Subject = _T("simple email from Visual C++ with gmail account");
    // Set email body
    oSmtp->BodyText = _T("this is a test email sent from Visual C++ project with Gmail");

    // Gmail SMTP server address
    oSmtp->ServerAddr = _T("smtp.gmail.com");

    // Gmail user authentication should use your
    // Gmail email address as the user name.
    // For example: your email is "gmailid@gmail.com", then the user should be "gmailid@gmail.com"
    oSmtp->UserName = _T("gmailid@gmail.com");

    // Create app password in Google account
    // https://support.google.com/accounts/answer/185833?hl=en
    oSmtp->Password = _T("your app password");

    // Use TLS 587 port,
    oSmtp->ServerPort = 587;

    // detect SSL/TLS automatically
    oSmtp->ConnectType = ConnectSSLAuto;

    _tprintf(_T("Start to send email via gmail account ...\r\n"));

    if(oSmtp->SendMail() == 0)
    {
        _tprintf(_T("email was sent successfully!\r\n"));
    }
    else
    {
        _tprintf(_T("failed to send email with the following error: %s\r\n"),
            (const TCHAR*)oSmtp->GetLastErrDescription());
    }

    return 0;
}

Gmail SMTP OAUTH

The Gmail IMAP and SMTP servers have been extended to support authorization via the industry-standard OAuth 2.0 protocol. Using OAUTH protocol, user can do authentication by Gmail Web OAuth instead of inputting user and password directly in application.

Google will disable traditional user authentication in the future, switching to Google OAuth is strongly recommended now.

TLS 1.2

TLS is the successor of SSL, more and more SMTP servers require TLS 1.2 encryption now.

If your operating system is Windows XP/Vista/Windows 7/Windows 2003/2008/2008 R2/2012/2012 R2, and you got connection error with SSL/TLS connection, you need to enable TLS 1.2 protocol in your operating system like this:

Enable TLS 1.2 on Windows XP/Vista/7/10/Windows 2008/2008 R2/2012

Next Section

At next section I will introduce how to send email with Yahoo account.

Appendix

Comments

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