How can I set and get the text from a RichEditBox in an Windows 8 C++ App.
I already tried these two approaches, but the program keeps crashing at runtime
cpp
contentText->Document->Selection->GetTextViaStream(Windows::UI::Text::TextGetOptions::FormatRtf, outstream);
contentText->Document->GetText(Windows::UI::Text::TextGetOptions::FormatRtf, tempOutput);
.h
private:
Platform::String^* tempOutput;
Windows::Storage::Streams::IRandomAccessStream^ outstream;
If you program crashes, that's a good thing. It doesn't actually "crash". It throws an exception and your debugger, once attached, will catch it and tell you exactly what went wrong. Next time, start your application with F5. Once it crashes, the debugger will show you what line the problem is in and you can watch all variables to check what went wrong.
In this case, make sure that
contentText is not NULL
Document is not NULL
tempOutput is initialized to a real object
Example:
Platform::String^ tempOutput = gcnew Platform::String();
Related
As you can see by the title I have issues when copying files from a directory to another. The code works perfectly fine but when the files are in use, obviously I get an error. Is there any way I can skip these files? (that are in use) and simply move on to the next?
I have tried looking for a solution to my issue but it seems there isn't a function from what I've seen on the internet for filesystem, any information given helps. I provided the code below for copying files.
std::filesystem::copy("C:\\Users\\"+ user+"\\AppData\\Local\\tee\\test\\User Data", "C:\\Users\\"+user+"\\AppData\\Local\\tee\\test\\Application", std::filesystem::copy_options::overwrite_existing | std::filesystem::copy_options::recursive);
If you can't copy you will get an exception, if you don't catch that the program chrashes. You can skip the files if you catch the exception with a simple try-catch statement. eg.:
try{
std::filesystem::copy(/*Params*/);
}catch(...){
std::cout<<"cant-copy '"<<filename<<"'";
/*Handle it if you don't want to just ignore (sleep and try later or ask the user what to to...)*/
}
I'm trying to write vtkImageData as a DICOM. I keep getting an "Access Reading Violation" when I try to write the image.
Unhandled exception at 0x00007FFDA30ECA50 : 0xC0000005: Access violation reading location 0x000001BD38D5C000
Here is my code:
vtkSmartPointer<vtkDICOMWriter> dcmWriter = vtkSmartPointer<vtkDICOMWriter>::New();
dcmWriter->SetInputData(testDat);
dcmWriter->SetFileName(fullPath.toStdString().c_str());
dcmWriter->Update(); // this line breaks
dcmWriter->Write();
testDat is a vtkSmartPointer<vtkImageData> type and has data in it. Any thoughts on whats causing the error? I can't find anything similar online.
I followed this example: https://github.com/dgobbi/vtk-dicom/blob/master/Examples/TestDICOMWriter.cxx
I don't have metadata, but that shouldn't be a problem.
I need to make some guesses here because you didn't post all of your code, but I suspect that the problem happens in the following line:
dcmWriter->SetFileName(fullPath.toStdString().c_str());
toStdString() is most probably returning a temporary std::string (fullPath looks like a Qt QString), on which you call c_str(). After the statement, your temporary is destroyed and whatever you have passed to SetFileName is now a dangling pointer. Hence the segfault.
Try the following instead::
const auto pathString = fullPath.toStdString();
dcmWriter->SetFileName(pathString.c_str());
This should hopefully work fine. Even if not, it definitely is an issue with your code.
These lines are from the example you posted:
writer->SetFilePrefix("/tmp");
writer->SetFilePattern("%s/IM-0001-%04.4d.dcm");
and you use
dcmWriter->SetFileName(fullPath.toStdString().c_str());
It seems that vtkDICOMWriter writes several files so you probably need to provide a file pattern. Anyway, it's hard to guess why it gives a reading error and it's hard to help if you don't post a full working example.
Last, vtkDICOMWriter is not a class from vtk, it was released separetely (it seems) in 2017. This means it's not tested against the rest of VTK at every new release.
So if I write the following code:
MessageBoxA(0, "Yo, wazzup!", "A Greeting From Earth", 0);
the program crashes with an access violation when it exits. When I write the code like this:
int a;
a = MessageBoxA(0, "Yo, wazzup!", "A Greeting From Earth", 0);
it doesn't crash. Now I know why it crashes when it crashes thanks to another question I asked, also regarding argument-mismatching, but I don't know why it crashes.
So why does this cause an APPCRASH? I was always under the impression that calling a function that had a return-type, without actually giving one was safe, example:
int SomeFunction (void) {
std::cout << "Hello ya'll!\n";
return 42;
}
int main (void) {
int a;
// "Correct" ?
a = SomeFunction();
a = MessageBoxA(0, "Yo, wazzup!", "A Greeting From Earth", 0);
// "Incorrect" ?
SomeFunction();
MessageBoxA(0, "Yo, wazzup!", "A Greeting From Earth", 0);
}
When I run this kind of test "clean" (in a new file) I don't get any errors. It only seems to give an error with MessageBox/MessageBoxA when run in my program. Knowing the possible causes would help me pinpoint the error as the project code is too big to post (and I would need my friend's permission to post his code anyway).
Additional Info:Compiler = GCCPlatform = Windows
EDIT:
UpdateThanks everyone for your feedback so far. So I decided to run it through a debugger... Now Code::Blocks doesn't debug a project unless it is loaded from a project file (*.cbp) - AFAIK. So I created an actual project and copy-pasted our project's main file into the projects. Then I ran in debug mode and didn't get so much as a warning. I then compiled in build mode and it ran fine.Next, I decided to open a new file in Dev-C++ and run it through the debugging and later the final build process and again I got no errors for either build or debug. I cannot reproduce this error in Dev-C++, even with our main file (as in the one that causes the error in Code::Blocks).
ConclusionThe fault must lie in Code::Blocks. AFAIK, they both use GCC so I am pretty confused. The only thing I can think of is a version difference or perhaps my compiler settings or something equally obscure. Could optimizer settings or any other compiler settings somehow cause this kind of error?
The version with the return value does not crash because it had one int more on the stack. Your erroneous code reads over the bounds of the stack and then runs into an access violation. But if you have more on the stack you will not hit the guard page, because that is just enough extra stack. If the the erroneous code only reads it is sort of OK, but still broken.
We had one bit of WTF inducing code that was like so:
char dummy[52];
some_function();
There was thankfully a longish comment explaining that removing dummy, makes some_function crash. It was in a very old application so nobody dared touch it and the some_function was totally different module we had no control over. Oh yea and that application was running smoothly in the field for over 20 years in industrial installations, like refineries or nuclear power plants... ^_^
I have a Visual C++ 9 Win32 application that uses a third-party library. When a function from that library is called with a certain set of parameters the program crashes with "exception code 0xC000000D".
I tried to attach Visual Studio debugger - no exceptions are thrown (neither C++ nor structured like access violations) and terminate() is not called either. Still the program just ends silently.
How does it happen that the program just ends abnormally but without stopping in the debugger? How can I localize the problem?
That's STATUS_INVALID_PARAMETER, use WinDbg to track down who threw it (i.e. attach WinDbg, sxe eh then g.
Other answers and comments to the question helped a lot. Here's what I did.
I notices that if I run the program under Visual Studio debugger it just ends silently, but if I run it without debugger it crashes with a message box (usual Windows message box saying that I lost my unsaved data and everyone is sooo sorry).
So I started the program wihtout debugger, let it crash and then - while the message box was still there - attached the debugger and hit "Break". Here's the call stack:
ntdll.dll!_KiFastSystemCallRet#0()
ntdll.dll!_ZwWaitForMultipleObjects#20() + 0xc bytes
kernel32.dll!_WaitForMultipleObjectsEx#20() - 0x48 bytes
kernel32.dll!_WaitForMultipleObjects#16() + 0x18 bytes
faultrep.dll!StartDWException() + 0x5df bytes
faultrep.dll!ReportFault() + 0x533 bytes
kernel32.dll!_UnhandledExceptionFilter#4() + 0x55c bytes
//SomeThirdPartyLibraryFunctionAddress
//SomeThirdPartyLibraryFunctionAddress
//SomeThirdPartyLibraryFunctionAddress
//SomeThirdPartyLibraryFunctionAddress
//OurCodeInvokingThirdPartyLibraryCode
so obviously that's some problem inside the trird-party library. According to MSDN, UnhandledExceptionFilter() is called in fatal situations and clearly the call is done because of some problem in the library code. So we'll try to work the problem out with the library vendor first.
If you don't have source and debugging information for your 3rd party library, you will not be able to step into it with the debugger. As I see it, your choices are;
Put together a simple test case illustrating the crash and send it onto the library developer
Wrap that library function in your own code that checks for illegal parameters and throw an exception / return an error code when they are passed by your own application
Rewrite the parts of the library that do not work or use an alternative
Very difficult to fix code that is provided as object only
Edit You might also be able to exit more gracefully using __try __finally around your main message loop, something like
int CMyApp::Run()
{
__try
{
int i = CWinApp::Run();
m_Exitok = MAGIC_EXIT_NO;
return i;
}
__finally
{
if (m_Exitok != MAGIC_EXIT_NO)
FaultHandler();
}
}
I am now trying to use this Application Verifier debugging tool, but i am stuck, first of all: it breaks the program at a line that is simple variable set line (s = 1; for example)
Secondly, now when i run this program under debugger, my program seems to have changed its behaviour: i am drawing image, and now one of the colors has changed o_O, all those parts of the image that i dont draw on, has changed the color to #CDCDCD when it should be #000000, and i already set the default color to zero, still it becomes to #CDCDCD.
How do i make any sense to this?
Here is the output AV gave me:
VERIFIER STOP 00000002: pid 0x8C0: Access violation exception.
14873000 : Invalid address causing the exception
004E422C : Code address executing the invalid access
0012EB08 : Exception record
0012EB24 : Context record
AVRF: Noncontinuable verifier stop 00000002 encountered. Terminating process ...
The program '[2240] test.exe: Native' has exited with code -1073741823 (0xc0000001).
Typically when breakpoints are hit like this (via AV or an unhandled exception, etc.) inside a debugger, there is a green arrow pointing to a line of code. That arrow is pointing to the next statement to execute when the thread returns from the current function. Perhaps this green arrow is pointing to the line where you wrote "s = 1", but really the offending code is the line above it. Now I can't see your code so I can't exactly know for sure and I don't have enough rep to post a comment - but this is something that is easy to check the next time the breakpoint is hit.
I am willing to bet that s is NOT a "simple" variable. I'm much more likely to believe it's something like this:
class Foo;
int s;
void Bar() {
s = 1;
}
};
Sure, it looks like a simple s=1 statement, but in reality it is a this->s=1 statement. And if this is an invalid pointer, this->s isn't a proper variable either.