Qt QDateTime toString("h:m:s ap") ap/a/AP/a missing - qt

Question

I've noted the "ap/a/AP/a" is missing while converting a date to string. For "h:m:s ap", i.e., I get "11:5:42 ". The same happens for each of the "ap/a/AP/a" forms.
What I'm missing?
void DecoderBr1::recordOnFile(QDateTime dateTime, QByteArray ba)
{
QString filename(dateTime.toString("yyyy MMMM dd#HH.mm.ss zzz ap"));
filename.append(".log");
Recorder recorder;
recorder.recordFile(filename, ba);
}

Answer 1

It depends on your locale. Not every locale support AM/PM format.
For example, my default locale is "it_IT" and does not print "AM/PM". Setting another locale (e.g. "en_EN") instead works as expected.
QDateTime t = QDateTime::fromString("2015-07-16T19:20:30+01:00", Qt::ISODate);
QString st = t.toString("yyyy MMMM dd#HH.mm.ss zzz ap");
QString locale_st_HH = QLocale("en_EN").toString(t, "yyyy MMMM dd#HH.mm.ss zzz ap");
QString locale_st_hh = QLocale("en_EN").toString(t, "yyyy MMMM dd#hh.mm.ss zzz ap");
qDebug() << st;
// With italian locale does not print AM/PM
// "2015 luglio 16#19.20.30 000 "
qDebug() << locale_st_HH;
// With en_EN locale it works
//"2015 July 16#19.20.30 000 pm"
qDebug() << locale_st_hh;
// With en_EN locale it works
// With hh it prints 07 pm instead of 19 pm // Credits to #t3ft3l--i
//"2015 July 16#07.20.30 000 pm"

Answer 2

Not all locale support this format of QDateTime output.
For result you are need create variable QLocale with parameters locale(language, country), which support it. For example:
QLocale eng(QLocale::English, QLocale::UnitedStates);
Then you can use QLocale::toString() method with chosen locale like this:
qDebug() << eng.toString(datetime, "yyyy MMMM dd#HH.mm.ss zzz ap");
Works for me at your example. And this way don't substitute your native locale.