C++ (Qt)
 QTextCodec *xcodec = QTextCodec::codecForName("Windows-1251");
 QString text = xcodec->fromUnicode(ui->textLineEdit->text());
 QUrl param( text );
 QString url = QString("/my_script.php?mytext=" + param.toEncoded());
 

PHP
<?
if(isset($_POST['mytext']) && $_POST['mytext']=="hello") {
echo "good";
}elseif(isset($_POST['mytext']) && $_POST['mytext']=="russky_tekst") {
echo "good too";
}else{
echo "bad";
}
?>
 

C++ (Qt)
   QByteArray ba("mytext=");
    ba.append( text.toUtf8() );
    http->request(header,ba);
 

C++ (Qt)
   QByteArray ba("mytext=");
    ba.append(text);
    http->request(header,ba);