doc: Add warning about QTextLayout::beginLayout() and clearLayout()

If you keep around QTextLines referring to the previous contents of
the layout, you can experience crashes when using these after the
layout has been cleared. Since QTextLine is a value type, this is
not very obvious in the API, so we should at least give a warning
in the docs.

Task-number: QTBUG-60804
Change-Id: I81b2b640eec5f62b0af1e878aadd9fa23654ec18
Reviewed-by: Konstantin Ritt <ritt.ks@gmail.com>
Reviewed-by: Venugopal Shivashankar <Venugopal.Shivashankar@qt.io>
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>
This commit is contained in:
Eskil Abrahamsen Blomfeldt 2017-05-16 10:04:03 +02:00
parent c21cee827f
commit 33c59be551

View File

@ -630,6 +630,9 @@ Qt::CursorMoveStyle QTextLayout::cursorMoveStyle() const
/*!
Begins the layout process.
\warning This will invalidate the layout, so all existing QTextLine objects
that refer to the previous contents should now be discarded.
\sa endLayout()
*/
void QTextLayout::beginLayout()
@ -673,6 +676,9 @@ void QTextLayout::endLayout()
Clears the line information in the layout. After having called
this function, lineCount() returns 0.
\warning This will invalidate the layout, so all existing QTextLine objects
that refer to the previous contents should now be discarded.
*/
void QTextLayout::clearLayout()
{