Looks like the SIGNAL loadFinished(bool) is not emitted anymore with Qt 6.8.1
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@Volker75 said in Looks like the SIGNAL loadFinished(bool) is not emitted anymore with Qt 6.8.1:
run your code. It looks like it is working,
So we agree that the statement that, "the SIGNAL loadFinished(bool) is not emitted anymore with Qt 6.8.1," is false.
The reports from valgrind have nothing to do with the problem.
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Ok. Sorry. ChrisW67. Thank you for your help. It helped us to locate the bug a bit closer. Yes. That is true. My header is wrong. My code is fine and also your code is fine. My and your applications (binaries/executables) are wrong, because there is at least one bug in Qt or in libxcb.so.1.1.0.
Sadly that is out of my scope and skill level. Can anyone report this well and hunt it down?
I bet that this or a very similar bug is also the reason for the other bug I reported some time ago:
https://forum.qt.io/topic/160116/qtwebenginecore-dll-sometimes-not-found?_=1736677825304 -
@Volker75 said in Looks like the SIGNAL loadFinished(bool) is not emitted anymore with Qt 6.8.1:
My header is wrong.
Don't know what this means.
because there is at least one bug in Qt or in libxcb.so.1.1.0.
Don't know what you are referring to. Don't think anyone can act on this. My understanding is that you reported signal not working, now you acknowledge it works, so don't know what bug you are referring to.
Can anyone report this well and hunt it down?
I don't see what others have to hunt down which is wrong, or why they would do so.
https://forum.qt.io/topic/160116/qtwebenginecore-dll-sometimes-not-found?_=1736677825304
I don't see why, whatever that turned out to be about, it is particularly related to anything else here. Especially if it is "intermittent".
To report a bug you need to have a small, complete piece of code which illustrates a problem. I think two other people have reported something like @ChrisW67's code seems to run fine, and you may be in that situation now, I don't know. I am not sure anyone will be interested in reports from valgrind necessarily counting as bugs, only if results in bad behaviour,
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"My header" = not in the code. Header of this topic/post in the forum.
I am refereeing to the valgrind logfile that i added. Did you ever used valgrind? It is a very nice tool and you can hunt down bugs in your code very well. It shows you where the bug is located.
If you watch the logfile, then you can see where the bug is located. Sadly valgrind refer to files that are out of my scope. The bug is not in my source. The bug is in functions that I call only.As far as i can see and understand it, there is a wrong pointer (Quote from the log file: "vector[0]) points to uninitialized byte(s)".). It points to a wrong place and that is why the function doesn't do what it should do. It was only luck that is was running fine. Similar to the other bug that I report. It is the same software and the same code and there it crashes with Windows 10 Citrix and Qt 6.7.2 even the exact code is running fine on 10 other computers with Qt 6.7.2 (Windows, Linux, Windows 10 local, MacOS, ...). So there it was only just luck.
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@Volker75
Yes, I have used valgrind many times. Yes, it can be a useful tool. Yes, it can always return false positives. No, I don't think anyone particularly will look into this, especially withQWebEngine, unless some behaviour is demonstrably wrong. Which as I understand it you do not have. You still say "why the function doesn't do what it should do" but I haven't seen a consistent report of something going wrong, else the other guys would have said so, valgrind report apart. Maybe I'm mistaken and someone else will look into this, but I wouldn't hold your breath. -
In my source it crashes every time under Linux 6.8.1!
Sadly it is large and so you want to have a smaller file of course, but then he bug doesn't occur.
It is like if I use a Qt function like this:
qt_foo(myCode.size());And in this Qt function is source like this: (This is not the real source. Only a bad example):
a[10];
...
for(int i=0; i<x; i++)
sum+=a[i];
}and you tell me: "Ohh... Wait: Your example code is too large. You must do a smaller sample code and prove that it doesn't work. Nobody will check such a large example. Your sample code is only allowed to have a small example that doesn't work."
My source code is sadly large. I can't make my source code smaller. If I make my source code smaller, then it is just higher luck that the bug doesn't occur. -
@Volker75
This forum is a user from, for users of Qt just like yourself. It is not a The Qt Company forum. If you want to report a bug that is done at TQtC https://bugreports.qt.io/. I think you will find they want a small program which reproduces bad behaviour. I don't know that they will look at your larger existing application, but up to you.In my source it crashes every time under Linux 6.8.1!
I agree that is problematic. You might supply them with the stack trace on crash, which you have not shown us.
I pay 50€ to the guy that fix this bug.
LOL :)
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Maybe am am not skilled enough with gdb.
I used gdb and used "r". And tried to get the crash.
Then I get this error:Thread 1 "Test" received signal SIGSEGV, Segmentation fault. Downloading source file /home/qt/work/qt/qtwebengine/src/webenginewidgets/api/qwebengineview.cpp QWebEngineView::page (this=0x555556a22710) at /home/qt/work/qt/qtwebengine/src/webenginewidgets/api/qwebengineview.cpp:1058 Warnung: 1058 /home/qt/work/qt/qtwebengine/src/webenginewidgets/api/qwebengineview.cpp: Datei oder Verzeichnis nicht gefundenIt is translated: File or Folder not found
So similar to the bug that i descriped in the other topic that i linked a few posts ago.Please give me more advice what I can do to locate the bug.
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Sorry, I forgot the bt stuff. I hope anyone understand it:
[Thread 0x7fff7cc006c0 (LWP 13329) exited] Thread 1 "Test" received signal SIGSEGV, Segmentation fault. Downloading source file /home/qt/work/qt/qtwebengine/src/webenginewidgets/api/qwebengineview.cpp QWebEngineView::page (this=0x555556a22710) at /home/qt/work/qt/qtwebengine/src/webenginewidgets/api/qwebengineview.cpp:1058 Warnung: 1058 /home/qt/work/qt/qtwebengine/src/webenginewidgets/api/qwebengineview.cpp: Datei oder Verzeichnis nicht gefunden (gdb) bt #0 QWebEngineView::page (this=0x555556a22710) at /home/qt/work/qt/qtwebengine/src/webenginewidgets/api/qwebengineview.cpp:1058 #1 0x00007ffff7f50f26 in QWebEngineView::setHtml (this=<optimized out>, html=<Fehler beim Lesen der Variable: Cannot access memory at address 0x7fffffffc038>, baseUrl=...) at /home/qt/work/qt/qtwebengine/src/webenginewidgets/api/qwebengineview.cpp:1102 #2 0x0000555555ae0436 in operator() (__closure=0x555556a59390) at src/timetableprintform.cpp:58 #3 0x0000555555ae0ced in operator() (__closure=0x7fffffffc120) at ../../../Qt6.8/6.8.1/gcc_64/include/QtCore/qobjectdefs_impl.h:141 #4 0x0000555555ae0d94 in QtPrivate::FunctorCallBase::call_internal<void, QtPrivate::FunctorCall<QtPrivate::IndexesList<>, QtPrivate::List<>, void, TimetablePrintForm::TimetablePrintForm(QWidget*)::<lambda()> >::call(TimetablePrintForm::TimetablePrintForm(QWidget*)::<lambda()>&, void**)::<lambda()> >(void **, struct {...} &&) (args=0x7fffffffc258, fn=...) at ../../../Qt6.8/6.8.1/gcc_64/include/QtCore/qobjectdefs_impl.h:65 Backtrace stopped: Cannot access memory at address 0x7fffffffc108 -
Apologies for being a bit abrupt in my last post.
I have posted two pieces of code. The first was a simple one-widget form that looked a bit like the problem statement (and worked when the obvious other elements were added), and the second was a self-contained example that worked without addition. There was no intent that these were to be copied and pasted into anywhere as a solution.
Based on the backtrace I would start with the assumption that, at line 58 of your code, the
viewpointer is invalid (probably not null). This could be because it is not initialised yet, the referenced object has been deleted, you have two variables calledviewwith one (invalid) masking the other (valid) etc.
