How can I print Qt:HANDLE on linux? (Qt5)

Question

As a means to verify which thread my code is actually running under I use QThread::currentThreadId(). However the Qt::HANDLE type that is returned from this function is according to the documentation a platform dependant typedef. On my platform (Linux) it was simply a typedef for void * (typeless pointer).

So how would I go about printing this using for example qDebug(), and how about converting it to a QString?

You could just dump `QThread::currentThread`, btw. – peppe Aug 07 '16 at 09:06 — peppe, Aug 07 '16 at 09:06

Mr. Developerdude · Accepted Answer · 2023-06-03T19:49:03.423

I fixed this myself with the following two helping functions. Note that I opted for using void * as the type instead of Qt::HANDLE as this might be useful in other cases and other platforms as well.

// Allow Qt::HANDLE and void * to be streamed to QDebug for easier threads debugging
QDebug operator <<(QDebug d, void *p){
    d.nospace() << QString::number((long long)p, 16);
    return d.space();
}

// Allow Qt::HANDLE and void * to be added together with QString objects for easier threads debugging
const QString operator+ ( const QString &s, void *p ){
    return (s+ QString::number((long long)p, 16));
}

score 2 · Answer 2 · edited Mar 05 '23 at 14:46

2

I prefer this way, maybe you create a qstring variable and then you can print it even setText() by using this qstring variable for some widgets.

QString id=QString( "%1" ).arg(static_cast<int>(QThread::currentThreadId()), 16);
ui->user->setText(id);
this->setWindowTitle(id);

edited Mar 05 '23 at 14:46

Mr. Developerdude

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answered Aug 07 '19 at 10:51

xiaowen

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Hi! I was explicitly looking for how to print the handle with qDebug(), but your solution is definitely useful for converting to QString! Welcome to Stack Overflow :) – Mr. Developerdude Aug 07 '19 at 12:26

How can I print Qt:HANDLE on linux? (Qt5)

2 Answers2