不要使用wp\\u登录功能，因为它已被弃用，请使用wp_signon.wp\\u signon函数在失败时返回wp\\u Error，因此使用它来评估条件，如下所示。

<?php
if ( \'POST\' == $_SERVER[\'REQUEST_METHOD\'] && !empty( $_POST[\'action\'] ) &&  $_POST[\'action\'] == \'log-in\' ) :

$login = wp_signon( array( \'user_login\' => $_POST[\'user-name\'], \'user_password\' => $_POST[\'password\'], \'remember\' => $_POST[\'remember-me\'] ), false );

if ( !is_wp_error($login) ){ 
save_message( \'success\', __( \'You have successfully Login.\', \'frontendprofile\' ) );
unset($_POST);
wp_redirect( get_permalink( 4 ) );
}

endif;
?>

您需要设置cookie，我对您的代码进行了如下修改：

Updated

<?php
function parse_user($info = null, $return = \'object\') {
    if ( is_null( $info ) ) {
        global $current_user;
        if ( empty( $current_user->ID ) ) return null;
        $info = get_userdata( $current_user->ID );
    }
    elseif ( empty( $info ) ) {
        return null;
    }
    if( $return == \'ID\' ) {
        if ( is_object( $info ) ) return $info->ID;
        if ( is_numeric( $info ) ) return $info;
    }
    elseif( $return == \'object\' ) {
        if ( is_object( $info ) && $info->ID) return $info;
        if ( is_object( $info )) return get_userdata( $info->ID );
        if ( is_numeric( $info ) ) return get_userdata( $info );
        if ( is_string( $info ) ) return get_userdatabylogin( $info );
    }   
    else {
        return null;
    }
}

function wp_login_user_po9856($username, $password, $remember) {
    // Get the user based on the username from the POST
    $user = parse_user($username);

    // Remove html tags from the variables
    $username = strip_tags($username);
    $password = strip_tags($password);

    // Validate the Form Data
    if(!wp_check_password( $password_stripped, $user->user_pass ) ) return new WP_Error(\'incorrect_password\', "Wrong Password!");

    // User login
    $login = wp_signon(array(\'user_login\' => $username, \'user_password\' => $password, \'remember\' => (bool)$remember));
    if (is_wp_error($login))
        return $login;

    // Unset
    unset($_POST);

    // Custom Message
    save_message( \'success\', __( \'You have successfully Login.\', \'frontendprofile\' ) );

    // Redirection
    wp_redirect(get_permalink( 4 ));
}
if ( \'POST\' == $_SERVER[\'REQUEST_METHOD\'] && @$_POST[\'action\'] == \'log-in\')
{
    wp_login_user_po9856($_POST[\'user-name\'], $_POST[\'password\'], $_POST[\'remember-me\']);
}