How to convert quint64 to 4 byte QByteArray
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How can I convert a quint64 into a 4 byte QByteArray?
I have a quint64 with the value of 19
quint64 length = 19;Note: The length could also be much larger. I have to pass it to a QTcpSocket. The protocol requires that the first 4 bytes are the size of the whole message.
The QByteArray should look like this:
\x13\x00\x00\x00\How can I do that?
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Use a QDataStream with a QBuffer:
QBuffer buf; buf.open(QBuffer::ReadWrite); QDataStream stream(&buf); qint64 v=19; stream<<v; QByteArray arr=buf.buffer();The array looks like:
"\x00\x00\x00\x00\x00\x00\x00\x13"
By default QDataStream use big endian ( you can change to little endian)
The array is 8 bytes length (qint64=8bytes)
If you really want 4 bytes in length, you must use qint32 instead. -
Use a QDataStream with a QBuffer:
QBuffer buf; buf.open(QBuffer::ReadWrite); QDataStream stream(&buf); qint64 v=19; stream<<v; QByteArray arr=buf.buffer();The array looks like:
"\x00\x00\x00\x00\x00\x00\x00\x13"
By default QDataStream use big endian ( you can change to little endian)
The array is 8 bytes length (qint64=8bytes)
If you really want 4 bytes in length, you must use qint32 instead.