Hi,
Does it work if you don't pass 'this' as the third argument to connect?
I never use that particular overload of connect. I usually pass the
lambda as the third argument.
Hope that helps, Tony
On 8/02/2020 10:03 am, Scott Bloom wrote:
Are you sure the function is getting called (via a break point)?
-----Original Message-----
From: Interest [mailto:interest-boun...@qt-project.org] On Behalf Of Jonathan
Purol
Sent: Friday, February 7, 2020 2:44 PM
To: Qt Project <interest@qt-project.org>
Subject: [Interest] Signal/Slot connection fails, even though
QMetaObject::activate is called
Hello everyone,
I have a QMainWindow subclass called `text_editor` with a function `save` which
looks as follows:
```cpp
void text_editor::save() {
_textbox->document()->setModified(false);
_textbox->setFocus();
emit saved();
}
```
I now connect to that slot in another class like this:
```cpp
_information_editor = new text_editor{this};
connect(
_information_editor,
&text_editor::saved,
this,
[=]() {
std::cout << "hello\n";
}
);
```
I have verified that the signal is emitted, in fact, the method generated by
the moc:
```cpp
// SIGNAL 0
void text_editor::saved()
{
QMetaObject::activate(this, &staticMetaObject, 0, nullptr); } ``` is
definitely called (verified with gdb and some other debugging shenenigans).
In addition, the connection object returned by `connect` is valid, as verified
by its implicit bool-cast operator.
However, "hello" is never printed. I suspected this could be because
`text_editor` inherits from `QMainWindow` and could have a different thread affinity, so
I tried the following things:
1. Move the editor to the same thread as the object which establishes the
connection 2. Use a QueuedConnection 3. Connect to the slot from WITHIN the
text editor itself, making sure that we are 100% on the same slot
and none of them worked.
Just for clarification, the print of "hello" is only an example, so even if
there was some issue with that, I would have detected it, the actual code is of course
different.
I'm really out of luck here, and would appreciate any help.
Sincerely,
Folling
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