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c++qtc++11qbytearrayqt5.6

Is there a shorter way to initialize a QByteArray?

In my program I work a lot with serial communication so QByteArray is used very often.

I was wondering if there was a shorter way to initialize a QByteArray with specific bytes than:

const char test_data[] = {
    static_cast<char>(0xB1), static_cast<char>(0xB2),
    0x5, static_cast<char>(0xFF),
    static_cast<char>(0xEE), static_cast<char>(0xEE),
    static_cast<char>(0x0)}; // Note QByteArray should be able to hold 0 byte
const QCanBusFrame frame = QCanBusFrame(0xA1, QByteArray(test_data));

The static_cast<char> is necessary because otherwise C++11 gives an error about narrowing, because the range 0x7F to 0xFF is bigger than a char could fit--but a char is what the QByteArray constructor asks for.

This is the QByteArray constructor being used:

QByteArray::QByteArray(const char *data, int size = -1)

Solution

  • Being inspired by the answers above this is what I finally came up with:

    const quint8 testData[] {0xB1, 0x00, 0xB2, 0x00};
const QCanBusFrame cFrame = QCanBusFrame(
    0xA1, QByteArray(reinterpret_cast<const char*>(testData), sizeof(testData)));

    I much prefer to have the bytes as byte numbers rather than literal characters when working with serial communication.

    After having a discussion on ##c++ I was advised that reinterpret_cast is appropriately used in this situation.