php-mail-sender.php

<pre><?php
/*
Snippet Name: Test default mail sender
Version: 1.0.1
Snippet URI: https://github.com/szepeviktor/wordpress-plugin-construction
License: The MIT License (MIT)
Author: Viktor Szépe
*/

test_mail_sender();

function test_mail_sender( $to = 'admin@szepe.net' ) {
    ini_set( 'display_errors', 1 );
    error_reporting( E_ALL );

    if ( function_exists( 'posix_getuid' ) ) {
        $uid = posix_getuid();
    } else {
        $uid = '??';
    }
    if ( function_exists( 'posix_geteuid' ) ) {
        $euid = posix_geteuid();
    } else {
        $euid = '??';
    }
    if ( function_exists( 'posix_getpwuid' ) ) {
        $real_user = posix_getpwuid( $uid );
        $effective_user = posix_getpwuid( $euid );
    } else {
        $real_user = $uid;
        $effective_user = $euid;
    }
    if ( function_exists( 'posix_getcwd' ) ) {
        $cwd = posix_getcwd();
    } else {
        $cwd = getcwd();
    }

    $subject = sprintf( '[Default mail sender] First mail from %s', $_SERVER['SERVER_NAME'] );
    $message = sprintf( 'SAPI: %s\nreal user: %s\neffective user: %s\ncurrent dir: %s\nPHP version: %s',
        var_export( php_sapi_name(), true ),
        var_export( $real_user, true ),
        var_export( $effective_user, true ),
        var_export( $cwd, true ),
        var_export( phpversion(), true )
    );
    $headers = sprintf( 'X-Mailer: PHP/%s', phpversion() );
    $mail = mail( $to, $subject, $message, $headers );
    printf( 'mail() to %s returned: %s', $to, var_export( $mail, true ) );
}