path: root/src/widgets/widgets/qmenu.cpp
diff options
authorGiuseppe D'Angelo <>2020-04-19 19:56:18 +0200
committerGiuseppe D'Angelo <>2020-09-03 07:00:31 +0200
commit25351dcc549f1daddf5e2ae8a242191174342a3e (patch)
tree97436200219470e7eee4096038e4da6e8df06835 /src/widgets/widgets/qmenu.cpp
parentf03b2f7711e3a0e90fb21672273959a2a9ed1c38 (diff)
Long live QKeyCombination!
C++20 via P1120 is deprecating arithmetic operations between unrelated enumeration types, and GCC 10 is already complaining. Hence, these operations might become illegal in C++23 or C++26 at the latest. A case of this that affects Qt is in key combinations: a QKeySequence can be constructed by summing / ORing modifiers and a key, for instance: Qt::CTRL + Qt::Key_A Qt::SHIFT | Qt::CTRL | Qt::Key_G (recommended, see below) The problem is that the modifiers and the key belong to different enumerations (and there's 2 enumerations for the modifier, and one for the key). To solve this: add a dedicated class to represent a combination of keys, and operators between those enumerations to build instances of this class. I would've simply defined operator|, but again docs and pre-existing code use operator+ as well, so added both to at least tackle simple cases (modifier + key). Multiple modifiers create a problem: operator+ between them yields int, not the corresponding flags type (because operator+ is not overloaded for this use case): Qt::CTRL + Qt::SHIFT + Qt::Key_A \__________________/ / int / \______________/ int Not only this loses track of the datatypes involved, but it would also then "add" the key (with NO warnings, now its int + enum, so it's not mixing enums!) and yielding int again. I don't want to special-case this; the point of the class is that int is the wrong datatype. Everything works just fine when using operator| instead: Qt::CTRL | Qt::SHIFT | Qt::Key_A \__________________/ / Qt::Modifiers / \______________/ QKeyCombination So I'm defining operator+ so that the simple cases still work, but also deprecating it. Port some code around Qt to the new class. In certain cases, it's a huge win for clarity. In some others, I've just added the necessary casts to make it still compile without warnings, without attempting refactorings. [ChangeLog][QtCore][QKeyCombination] New class to represent a combination of a key and zero or more modifiers, to be used when defining shortcuts or similar. [ChangeLog][Potentially Source-Incompatible Changes] A keyboard modifier (such as Qt::CTRL, Qt::AltModifier, etc.) should be combined with a key (such as Qt::Key_A, Qt::Key_F1, etc.) by using operator|, not operator+. The result is now an object of type QKeyCombination, that stores the key and the modifiers. Change-Id: I657a3a328232f059023fff69c5031ee31cc91dd6 Reviewed-by: Volker Hilsheimer <>
Diffstat (limited to 'src/widgets/widgets/qmenu.cpp')
1 files changed, 1 insertions, 1 deletions
diff --git a/src/widgets/widgets/qmenu.cpp b/src/widgets/widgets/qmenu.cpp
index c2ef383d28..9007d2af78 100644
--- a/src/widgets/widgets/qmenu.cpp
+++ b/src/widgets/widgets/qmenu.cpp
@@ -3406,7 +3406,7 @@ void QMenu::keyPressEvent(QKeyEvent *e)
QAction *act = d->;
QKeySequence sequence = QKeySequence::mnemonic(act->text());
- int key = sequence[0] & 0xffff;
+ int key = sequence[0].toCombined() & 0xffff; // suspicious
if (key == c.unicode()) {
if (!first)