Appending one QByteArray to another QByteArray

Question

I wrote the following function, which is supposed to allow me to append some input QByteArray data to a private QByteArray inside of my class:

void addQByteArray(QByteArray* array)
{
    p_commandArray.append(array);
}

My understanding is that the append function should also accept a QByteArray as a parameter, but I'm getting this error when I try to compile:

error: invalid conversion from ‘QByteArray*’ to ‘char’ [-fpermissive] p_commandArray.append(array); ^

What am I doing wrong here?

463035818_is_not_an_ai · Accepted Answer · 2020-01-07T16:54:10.427

4

Yes QByteArray::append has an overload that you can pass a QByteArray (more precicelsy a const QByteArray&), but what you attempt to pass is a pointer to QByteArray.

Either

void addQByteArray(QByteArray& array)
{
    p_commandArray.append(array);
}

or

void addQByteArray(QByteArray* array)
{
    p_commandArray.append(*array);
}

Prefer the first (passing a reference), because using pointers only makes sense when a nullptr is a valid parameter, but when you pass a nullptr you shall not dereference it.

The error message you get is due to another overload of append that takes a char as parameter.

edited Jan 07 '20 at 16:54

answered Jan 07 '20 at 16:13

463035818_is_not_an_ai

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Thank you for the feedback. It woks like a charm now :-). – Jason O Jan 07 '20 at 16:52
For the null case there's the default constructed bytearray (and .isNull()), so there is almost no case where one would pass a bytearray by pointer. – Frank Osterfeld Jan 07 '20 at 17:37
@FrankOsterfeld the only reason I included it is because thats what OP had originally – 463035818_is_not_an_ai Jan 07 '20 at 17:41

score 2 · Answer 2 · answered Jan 07 '20 at 16:13

2

QByteArray::append accepts const QByteArray&, but you give it a pointer. Give it an object:

void addQByteArray(QByteArray* array) {
    p_commandArray.append(*array);
    //                    ^ dereference
}

answered Jan 07 '20 at 16:13

Evg

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Appending one QByteArray to another QByteArray

2 Answers2