RLSegmentation fault about WMessageBox...
Added by Richard Li almost 13 years ago
Wt's version is 3.3.1
I use it like these:
1.I create a modal WMessageBox box in WApplication's thread, implemented like the static method WMessageBox::show().
then I connect a slot to a signal:
the slot code:
void slot { box.setText("1234567"); }
the signal is emit from a thread out of the WApplication.
When I catch the signal, segmentation fault.
2.I change the slot:
void slot { box.accept(); }
then connect a new slot2 to box.finished()
box.finished().connected(boost::bind(&class::slot2, class));
void slot2 { WMessageBox::show(...); }
segmentation fault.
I can make sure the code has went into the slot2.
Replies (6)
WD RE: Segmentation fault about WMessageBox... - Added by Wim Dumon almost 13 years ago
Do you have a stack trace of the segmentation fault?
What is your boost version? Using boost.signals or boost.signals2?
Wim.
RL RE: Segmentation fault about WMessageBox... - Added by Richard Li almost 13 years ago
Well, I can't see the stack in arm....the valgrind worked incorrect....
But there is another phenomenon:
1.In the first test:
In the slot, I use another code
std::cout << "-----------------" << std::endl;
instead of box.setText();
It will be worked well.
2.In the second test:
In the slot2, I use another code
std::cout << "-----------------" << std::endl;
instead of WMessageBox::show(...);
It will be worked well.
It seems that if I want control the box in the slot, only accept() method can correctly work.
RL RE: Segmentation fault about WMessageBox... - Added by Richard Li almost 13 years ago
boost version is 1.47.0
KD RE: Segmentation fault about WMessageBox... - Added by Koen Deforche almost 13 years ago
Hey Richard,
Can you post a complete self-contained test case? This will help us in either point out what you're doing wrong or reproduce the problem ourselves.
Regards,
koen
RL RE: Segmentation fault about WMessageBox... - Added by Richard Li almost 13 years ago
I thought I have found what causes this problem...
In my problem, I have at least two thread use the slot or slot2.
When I use the boost::signal,the slot is a callback function and actually running in the thread out of the WApplication which have no WApplication's
environment. So that if I change the Wt's object in the slot, segmentation fault occured.
KD RE: Segmentation fault about WMessageBox... - Added by Koen Deforche almost 13 years ago
Hey,
You can't just access Wt objects from different threads. If you want that, you need to read up on Wt's WApplication::UpdateLock
Regards,
koen