WordPress at a glance
function is not described

PHPMailer\PHPMailer

PHPMailer::isQmail() public WP 1.0

Send messages using qmail.

{} It's a method of the class: PHPMailer{}

No Hooks.

Return

null. Nothing.

Usage

$PHPMailer = new PHPMailer();
$PHPMailer->isQmail();

Code of PHPMailer::isQmail() WP 5.7.2

<?php
public function isQmail()
{
    $ini_sendmail_path = ini_get('sendmail_path');

    if (false === stripos($ini_sendmail_path, 'qmail')) {
        $this->Sendmail = '/var/qmail/bin/qmail-inject';
    } else {
        $this->Sendmail = $ini_sendmail_path;
    }
    $this->Mailer = 'qmail';
}