I get an unhandled exception if I close my program using Poco mutexes.
I use a global
Poco::Mutex mymutex ;
in my cpp file, because I have a static class for logging (I also tried to declare it as a static member, but I got the same error).
The relevant part of my code (it's a static function):
void Log::log(std::string message)
{
try
{
Poco::Mutex::ScopedLock lock(mymutex);
std::ofstream f("log.txt", std::ios_base::app) ;
f << message << std::endl ;
f.close() ;
}
catch (...)
{
}
}
This part of the code works great in my program (there are no lines on each other like before using mutexes), but after I close my program, I get the following error message:
Unhandled exception at 0x77c3a710 in myprogram.exe: 0xC0000005:
Access violation writing location 0x00000014.
I also tried to use mymutex.lock() and mymutex.unlock() before and after writing to the file, but I got the same error.
And I also tried this code:
while(!mymutex.tryLock())
Poco::Thread::sleep(30);
but it resulted an infinite loop, the program has not stopped after closing its window.
I use Visual Studio 2010 and Poco 1.4.
Related
I'm trying to create a program that, on execution, zips a given directory. Most of my errors have been resolved and I am hopefully getting to the end of this, but I still have the issue of an exception being thrown and a question regarding the program. I code in C++20 and on Visual Studio 2019.
I've come across this exact error when debugging the program:
Exception thrown at 0x76820B42 in aixLogger.exe: Microsoft C++ exception: bit7z::BitException at memory location 0x001AF440.
I already checked with a breakpoint what code is giving me this error:
catch (const BitException& ex) {
ex.what(); //<-
}
The code runs otherwise and isn't giving me any error messages, the breakpoint activates on the line I marked with an arrow (not actually part of my code).
To eliminate further possible edits I will add the rest of my code as well:
main.cpp
#include <QCoreApplication>
#include <string>
#include <iostream>
#include <filesystem>
#include <bit7z.hpp>
#include "main.h"
#include <bitcompressor.hpp>
namespace fs = std::filesystem;
using namespace bit7z;
using namespace std;
int main(int argc, char* argv[])
{
QCoreApplication a(argc, argv);
try {
Bit7zLibrary lib{ L"7z.dll" };
BitCompressor compressor{ lib, BitFormat::Zip };
//vector< wstring > files = { L"aretz/Downloads/test" };
wstring dir = { L"D: / local / aretz / Programmierung / git - workplace / aixLogger / test /" } ;
wstring zip = { L"zippedtest.zip" };
compressor.compressDirectory(dir, zip);
}
catch (const BitException& ex) {
ex.what();
}
return a.exec();
}
void AIXLogger::CompressDir() {
/*try {
Bit7zLibrary lib{ L"7z.dll" };
BitCompressor compressor{ lib, BitFormat::Zip };
vector< wstring > files = { L"C:/Users/aretz/Downloads/test" };
wstring zip = { L"zippedtest.zip" };
compressor.compressFiles(files, zip);
}
catch (const BitException& ex) {
ex;
}*/
}
main.h
#pragma once
#include <qwidget.h>
#include <qobject.h>
#include <bit7z.hpp>
class AIXLogger : public QWidget
{
Q_OBJECT
public slots:
public:
void CompressDir();
};
I've currently commented out the function CompressDir() as I can't call it in my main since it gives me either a syntax error or tells me the identifier is undefined.
Syntax Error:
AIXLogger.CompressDir(); the dot is marked as the error
identifier is undefined:
CompressDir();
I don't know what exactly is causing the catch to thrown an exception. From other posts I suspected that my paths for the files and directories are at fault, but changing them or moving my test directory didn't help at all. Removing the try and catch lines from my codeblock only adds the same error message where Exception Thrown is being replaced by Unhandled Exception. Thanks to anyone who can help.
I already checked with a breakpoint what code is giving me this error:
catch (const BitException& ex) {
ex.what(); //<-
}
The code runs otherwise and isn't giving me any error messages
The code isn't giving you any error message since you're not doing anything with the information provided by the thrown exception.
You're simply calling ex.what() without, for example, printing the error message string it returns, e.g., via std::cout.
the breakpoint activates on the line I marked with an arrow (not actually
part of my code).
I don't know what exactly is causing the catch to thrown an exception. From other posts I suspected that my paths for the files and directories are at fault, but changing them or moving my test directory didn't help at all.
The ex.what() error message should give you more details about the actual issue you're having.
By the way, I'm the author of the bit7z library, and from my experience and looking at the code you posted, I can think of some possible causes (the most common ones):
The program could not find the 7z.dll library.
Please ensure that the DLL is in the same directory as the executable or in one of the default DLL search paths of Windows.
The program could not find the directory path to be compressed.
As before, make sure that the path exists.
I'm trying to convert the functionality of our old code to a DLL.
One of the function wants to export from our old code use a dynamically linked DLL (that I'm gonna call other)
std::wstring otherDLL = L"C:\\PATH\\TO\\OTHER\\DLL"
if (!(libOther = LoadLibraryW(otherDLL.c_str()))){
return;
}
In our old code, this portion of code works just fine.
So I added in my new DLL the following code:
extern "C++" std::wstring test_load(void){
std::wstring otherDLL = L"C:\\PATH\\TO\\OTHER\\DLL"
if (!(libOther = LoadLibraryW(otherDLL.c_str()))){
return L"Not Loaded";
}
return L"Loaded";
}
(this function is not launched during DLLMain). If I try to launch test_load from my DLL in another exe
#include "MyNewDLL.h"
int main()
{
std::wcout << test_load();
}
I get following error
Unhandled exception at 0x7BDE20f3 (ucrtbased.dll) in Test.exe: 0xC00000005: Access violation reading location 0x00000000
What's strange is that if I try to load the OtherDLL from the main that is not inside MyNewDLL, there is no error and I can use it just fine.
Any Idea where my problem could come from ?
I have an exception is a dll i'm using when initializing a static local variable to a class instance.
The exception occurs when returning from the class constructor.
The exception I get in release is:
ConsoleApplication1.exe: 0xC0000005: Access violation reading location 0x00000000BA3529A2.
and in debug I get a debug assertion:
Debug Assertion Failed!
Program: E:\Sandbox\ConsoleApplication1\x64\Debug\ConsoleApplication1.exe
File: f:\dd\vctools\crt\crtw32\misc\dbgheap.c
Line: 1516
Expression: _CrtIsValidHeapPointer(pUserData)
This is the function that fail (Part of the CImg library which is excellent!):
static const CImg<Tuchar>& jet_LUT256() {
static CImg<Tuchar> colormap; // <--- static local variable decleration
// exception here. after returnning from the CImg constructor :-(
cimg::mutex(8);
if (!colormap) {
colormap.assign(1,4,1,3,0);
colormap[2] = colormap[3] = colormap[5] = colormap[6] = colormap[8] = colormap[9] = 255;
colormap.resize(1,256,1,3,3);
}
cimg::mutex(8,0);
return colormap;
}
When the project was running as an exe everything worked fine.
Problem started when I made it a dll, and used it in another exe.
Solved.
Found out that the problem was that I used the /NOENTRY property (big NONO!)
(because when I converted it from exe to dll I had a link error with unresolved function mainCRTStartup)
removed the /NOENTRY from Properties->Linker->Advanced and error is gone.
I am trying to define a variable from an external library in C++, Visual Studio 2010. It only works when I put it outside of the main function.
This code crashes:
#include "StdAfx.h"
#include <ogdf\basic\Graph.h>
#include <ogdf\basic\graph_generators.h>
int main()
{
ogdf::Graph g;
ogdf::randomSimpleGraph(g, 10, 20);
return 0;
}
It gives me an unhandheld exception: Access violation.
However, if it is outside main function, it works without any problem:
#include "StdAfx.h"
#include <ogdf\basic\Graph.h>
#include <ogdf\basic\graph_generators.h>
ogdf::Graph g;
int main()
{
ogdf::randomSimpleGraph(g, 10, 20);
return 0;
}
Do you have any how do I fix that? I assume, that it is caused by some kind of linking problem.
EDIT: It looks like the problem is not the initialization of the variable. It throws an exception, when the application exits.
int main()
{
ogdf::Graph g; // No problem
ogdf::randomSimpleGraph(g, 10, 20); // No problem
int i; // No problem
std::cin>>i; // No problem
return 0; // Throws an exception after read i;
}
Call stack:
The output is:
First-chance exception at 0x0126788f in graphs.exe: 0xC0000005: Access violation writing location 0x00000000.
Unhandled exception at 0x0126788f in graphs.exe: 0xC0000005: Access violation writing location 0x00000000.
Works on my machine™.
Esoteric errors like that are often a result of binary incompability. Basically, because of different compiler/preprocessor options, effective headers that your code and the library "see" are different.
For instance, if you have a library with following header code:
class Foo
{
#ifdef FOO_DEBUG
int debug_variable;
#endif
int variable;
};
Library function:
void bar(Foo& foo)
{
std::cout << foo.variable;
}
And client code:
Foo foo;
foo.variable = 666;
bar(foo);
If FOO_DEBUG is not in sync amongst client and the library, this will possibly crash and burn -- variable will have different expected offset.
In your case, I suspect one of the following may be true:
You have built the ogdf with different compiler than your code
If not, you ogdf and your code have different build configurations (Release vs Debug)
Both are debug, but you have defined OGDF_DEBUG (as recommended here)
You have different "Struct Member Alignment" setting
I got this error
Unhandled exception at 0x0049b946 in Program.exe: 0xC0000005: Access violation reading location 0x00000090.
and the error points to this line:
// thread.hpp ln 56
void run()
{
f(); // here <<
}
When trying to run this code:
void frameFunc()
{
for(;;)
{
//..........do something. it is too long to paste. (calculations)
}
}
int main()
{
boost::thread framethread(frameFunc);
framethread.join();
//........
}
The error will simply gone when I remove the loop in frameFunc.
Any kind of help would be appreciated :)
The code that you showed looks valid. I think the problem is inside the code that is not shown.