Sample code for 30+ languages & platforms
Swift

Send High Priority Email (SMTP, X-Priority header)

Demonstrates how to send high-priorty email (or lower priority email) by setting the X-Priority header field.

Chilkat Swift Downloads

Swift

func chilkatTest() {
    var success: Bool = false

    // This example requires the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    // The mailman object is used for sending and receiving email.
    let mailman = CkoMailMan()!

    // Set the SMTP server (obviously, use your SMTP server, not chilkatsoft.com)
    mailman.smtpHost = "smtp.chilkatsoft.com"

    // Set the SMTP login/password (if required)
    mailman.smtpUsername = "myUsername"
    mailman.smtpPassword = "myPassword"

    // Create a new email object
    let email = CkoEmail()!

    email.subject = "This is a test"
    email.body = "This is a test"
    email.from = "Chilkat Support <support@chilkatsoft.com>"
    success = email.add(to: "Chilkat Admin", emailAddress: "admin@chilkatsoft.com")
    // To add more recipients, call AddTo, AddCC, or AddBcc once per recipient.

    // To send high-priority email, 
    // add the X-Priority header field with the value "1" 
    // to indicate highest-priority.
    // A value of "3" is normal, which is the same as not setting
    // the X-Priority header at all, and "5" is the lowest. 
    // "2" and "4" are in-betweens.

    // Microsoft Outlook might add the following headers when
    // sending high-priority email.

    // X-Priority: 1 (Highest) 
    // X-MSMail-Priority: High 
    // Importance: High 

    // The X-Priority header alone is enough to make the email high-priority.

    email.addHeaderField(fieldName: "X-Priority", fieldValue: "1")

    // Call SendEmail to connect to the SMTP server and send.
    // The connection (i.e. session) to the SMTP server remains
    // open so that subsequent SendEmail calls may use the
    // same connection.  
    success = mailman.sendEmail(email: email)
    if success != true {
        print("\(mailman.lastErrorText!)")
        return
    }

    success = mailman.closeSmtpConnection()
    if success != true {
        print("Connection to SMTP server not closed cleanly.")
    }

    print("Mail Sent!")

}