Question

I am making a system that will be used to collect data from users. I know some will be spam! I just want to know if the mail function returns false if the email is not correct?

Say I have.

   <?php

    $to = "[e-mail]";
    $header = "From: {$to}";
    $subject = "Hi!";
    $body = "Hi,\n\nHow are you?";

    if (mail($to, $subject, $body, $header)) {
          echo("<p>Message successfully sent!</p>");
    } else {
          echo("<p>Message delivery failed...</p>");
    }

   ?>

Which message will be printed if the email is not correct?

If it does return false I want a “flag” to be stored with it in that database so the admins can review it and delete it.

Answer 1

Not necessarily.

Per the manual, the mail() function will return true if the message is accepted for delivery – but doesn’t guarantee that it will be delivered:

Returns TRUE if the mail was successfully accepted for delivery, FALSE
otherwise.

It is important to note that just because the mail was accepted for
delivery, it does NOT mean the mail will actually reach the intended
destination.