Why does select(QTextCursor::BlockUnderCursor) include an extra junk character?

[therefore]

Windows 7 SP1
MSVS 2010
Qt 4.8.4

I am using QTextCursor to grab each block's text. I use select(QTextCursor::BlockUnderCursor) to grab the text and then go to the next block with movePosition(QTextCursor::NextBlock). But when I again select(QTextCursor::BlockUnderCursor) I get an extra junk character in the QString and the anchor has moved to the end of the previous block.

Using this for text.txt:

A
B

A
B

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This code's comments walks through the issue and asks the questions:

#include <QTGui>
 int main(int argc, char *argv[])
{
    QApplication app(argc, argv);
    QMainWindow*          window = new QMainWindow;
    QTextEdit*            editor = new QTextEdit(window);
    QTextDocument*      document = new QTextDocument(window);
 
    editor->setDocument(document);
    QFile file("test.txt");
    if (file.open(QFile::ReadOnly | QFile::Text))
        editor->setPlainText(file.readAll());
 
    QTextBlock block = document->begin();
    QTextCursor* cursor = new QTextCursor(document);
    int pos = cursor->position();           // = 0
    int anchor = cursor->anchor();          // = 0
 
    cursor->select(QTextCursor::BlockUnderCursor);
    pos = cursor->position();               // = 1
    anchor = cursor->anchor();              // = 0
 
    QString text = cursor->selectedText();  // = "A"
    int size = text.size();                 // = 1
 
    cursor->movePosition(QTextCursor::NextBlock);
    pos = cursor->position();               // = 2
    anchor = cursor->anchor();              // = 2
 
    cursor->select(QTextCursor::BlockUnderCursor);
    pos = cursor->position();               // = 3
    anchor = cursor->anchor();              // = 1 Why not 2?
 
    text = cursor->selectedText();          // "B" in debugger
                                            // but text.at(0) = junk & test.at(1) = "B"
    size = text.size();                     // = 2 Why? Why not 1?
 
    return app.exec();
}

#include <QTGui>
 int main(int argc, char *argv[])
{
    QApplication app(argc, argv);
    QMainWindow*          window = new QMainWindow;
    QTextEdit*            editor = new QTextEdit(window);
    QTextDocument*      document = new QTextDocument(window);

    editor->setDocument(document);
    QFile file("test.txt");
    if (file.open(QFile::ReadOnly | QFile::Text))
        editor->setPlainText(file.readAll());

    QTextBlock block = document->begin();
    QTextCursor* cursor = new QTextCursor(document);
    int pos = cursor->position();           // = 0
    int anchor = cursor->anchor();          // = 0

    cursor->select(QTextCursor::BlockUnderCursor);
    pos = cursor->position();               // = 1
    anchor = cursor->anchor();              // = 0

    QString text = cursor->selectedText();  // = "A"
    int size = text.size();                 // = 1

    cursor->movePosition(QTextCursor::NextBlock);
    pos = cursor->position();               // = 2
    anchor = cursor->anchor();              // = 2

    cursor->select(QTextCursor::BlockUnderCursor);
    pos = cursor->position();               // = 3
    anchor = cursor->anchor();              // = 1 Why not 2?

    text = cursor->selectedText();          // "B" in debugger
                                            // but text.at(0) = junk & test.at(1) = "B"
    size = text.size();                     // = 2 Why? Why not 1?

    return app.exec();
}

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[norobro]

From the docs ( QTextCursor::selectedText() ):

Note: If the selection obtained from an editor spans a line break, the text will contain a Unicode U+2029 paragraph separator character instead of a newline \n character.

You can check by putting the following statement in your code:

qDebug() << QString("U+%1").arg(text.at(0).unicode(),0,16);

qDebug() << QString("U+%1").arg(text.at(0).unicode(),0,16);

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[therefore]

Thanks for the education! Now I get it. In other words, selecting the block includes the starting paragraph separator. The first block doesn't have a starting SEP. Therefore, need to exclude the first character if one wants to extract the text alone of subsequent blocks.

[norobro]

You're welcome. If you just want the text use QString::trimmed():

text = cursor->selectedText().trimmed();

text = cursor->selectedText().trimmed();

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