how to send email in c++ program

To send an email in a C++ program, you can use a library called "libcurl" which provides functions for sending HTTP requests, including sending emails. Here are the steps to send an email in C++ using libcurl:

Step 1: Include the necessary headers

#include <curl/curl.h>

This header file includes the necessary functions and data types for using libcurl.

Step 2: Initialize libcurl

curl_global_init(CURL_GLOBAL_DEFAULT);

This function initializes the libcurl library and should be called before using any other libcurl functions.

Step 3: Set up the email content

CURL *curl = curl_easy_init();
if (curl) {
  curl_easy_setopt(curl, CURLOPT_URL, "smtp://smtp.example.com");
  curl_easy_setopt(curl, CURLOPT_MAIL_FROM, "[email protected]");
  curl_easy_setopt(curl, CURLOPT_MAIL_RCPT, "[email protected]");
  curl_easy_setopt(curl, CURLOPT_USERNAME, "username");
  curl_easy_setopt(curl, CURLOPT_PASSWORD, "password");
  curl_easy_setopt(curl, CURLOPT_USE_SSL, CURLUSESSL_ALL);
  curl_easy_setopt(curl, CURLOPT_READFUNCTION, &read_callback);
  curl_easy_setopt(curl, CURLOPT_READDATA, &email_data);
}

In this step, you set up the email content by configuring various options using curl_easy_setopt function. The CURLOPT_URL option specifies the SMTP server URL, the CURLOPT_MAIL_FROM option sets the email sender address, the CURLOPT_MAIL_RCPT option sets the email recipient address, the CURLOPT_USERNAME and CURLOPT_PASSWORD options set the login credentials for the SMTP server, and the CURLOPT_USE_SSL option enables SSL/TLS encryption for the connection. Additionally, you need to set a callback function read_callback to provide the email data.

Step 4: Implement the callback function to provide email data

size_t read_callback(void ptr, size_t size, size_t nmemb, void userp) {
  EmailData email_data = (EmailData )userp;
  if (email_data->offset < email_data->length) {
    size_t copy_size = size * nmemb;
    if (email_data->offset + copy_size > email_data->length) {
      copy_size = email_data->length - email_data->offset;
    }
    memcpy(ptr, email_data->data + email_data->offset, copy_size);
    email_data->offset += copy_size;
    return copy_size;
  }
  return 0;
}

This callback function is responsible for providing the email data to libcurl. You need to implement this function according to your email content.

Step 5: Perform the email sending

CURLcode res = curl_easy_perform(curl);
if (res != CURLE_OK) {
  fprintf(stderr, "curl_easy_perform() failed: %s\n", curl_easy_strerror(res));
}

This function call performs the actual sending of the email using the configured options. The return value res indicates the success or failure of the operation.

Step 6: Clean up and finalize

curl_easy_cleanup(curl);
curl_global_cleanup();

These functions are used to clean up and finalize the libcurl resources.

Remember to replace the placeholder values with the actual values specific to your setup, such as the SMTP server URL, email addresses, login credentials, and email content.

This is a basic example of sending an email using libcurl in C++. You can further customize and enhance it according to your specific requirements.