Rust

Add an HTML Alternative Body to an Email

Demonstrates the Chilkat Email.AddHtmlAlternativeBody method, which adds an HTML alternative body. Combined with a plain-text body, it produces a multipart/alternative email that offers both representations of the same content. This example sets a plain-text body, adds an HTML alternative, and prints the resulting alternative count.

Background: A well-formed HTML email usually ships two versions of the body: a rich HTML version and a plain-text fallback, wrapped in a multipart/alternative container. The receiving client displays whichever it prefers — modern clients show the HTML, while text-only clients (or spam filters and accessibility tools) use the plain text. Providing both improves deliverability and ensures every recipient can read the message.

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Rust

// Demonstrates the AddHtmlAlternativeBody method, which adds an HTML alternative body to
// the email.  Combined with a plain-text body, this produces a multipart/alternative
// email that offers both representations.

let email = chilkat::Email::new();
email.set_subject("Plain-text and HTML alternatives");

// Start with a plain-text body.
email.set_text_body("This is the plain-text version of the message.", "text/plain");

// Add an HTML alternative, creating a multipart/alternative email.
let _ = email.add_html_alternative_body("<html><body><b>This is the HTML version.</b></body></html>");

println!("NumAlternatives = {}", email.num_alternatives());