C++ :: Invalid Access To Memory Location Using GlobalFree
Jan 11, 2013
Under Microsoft, I use GlobalAlloc and GlobalFree to dynamically allocate and free memory. Intermittently GlobalFree is reporting error 998 (GetLastError() - Invalid access to memory location). I've checked my logs of addresses returned by GlobalAlloc against those being freed by GlobalFree and when the problem occurs the address causing the error has been allocated by GlobalAlloc and has not been freed before since allocation.
I can't reproduce it. Currently I'm checking for error 998 from GlobalFree and ignoring it if it occurs - which is not satisfactory. I have one function (AllocMem) that calls GlobalAlloc and checks for errors and another function (FreeMem) which calls GlobalFree and checks for errors.
My program uses AllocMem and FreeMem everywhere memory is required or freed. AllocMem and FreeMem are in a DLL. The program is heavily threaded and a different thread may call AllocMem to the one that calls FreeMem. I don't believe I've got a race condition etc as all the code in the program containing the AllocMem and FreeMem calls are part of a CriticalSection using the same variable.
I recently started learning C++ and wanted to deep a bit into process memory reading for Windows, but I get an error I don't know how to fix. I'm using Visual Studio Express 2013 as my IDE and it tells me this, when I try to run and debug:
"Unhandled exception at 0x77E3E243 (ntdll.dll) in readProcessMemory.exe: 0xC0000005: Access violation reading location 0x00000043."
The Call Stack window says following: ntdll.dll!_NtRaiseException@12() Unknown ntdll.dll!_KiUserExceptionDispatcher@8() Unknown ntdll.dll!_RtlInitUnicodeString@8() Unknown > readProcessMemory.exe!main() Line 8 C++ [External Code]
And in the Output window is this: First-chance exception at 0x77E3E243 (ntdll.dll) in readProcessMemory.exe: 0xC0000005: Access violation reading location 0x00000043. Unhandled exception at 0x77E3E243 (ntdll.dll) in readProcessMemory.exe: 0xC0000005: Access violation reading location 0x00000043.
My code should be extremely simple, I'm just trying to find a Windows window. But here's the code.
Code: #include <windows.h> #include <iostream> using namespace std; int main(){
I have these two functions listed below. DoEvent() gets called from a window procedure whenever some event occurs. SetEvent() sets an element of the m_Events array a pointer to a Command object to handle the event. The array is zeroed in the constructor.
The error occurs on line 16 in the code in DoEvent(). Why the array is suddenly unreadable. When I call SetEvent() it works just fine, no problem.
When I step through the debugger in SetEvent i see that each element begins as 0 and the element I set is set properly. However, when I step through DoEvent() all elements in m_Events show "?????" "Unable to read memory".
I have a problem. Im testing character movement in c++ and when i compile and run this, then try to press arrow keys it says "Access violation writing location 0x011feff4.Unhandled exception at 0x770a15de in test.exe: 0xC0000005: Access violation writing location 0x011feff4.The program '[8404] test.exe: Native' has exited with code -1073741819 (0xc0000005)."
#include <iostream> #include <string> #include <Windows.h> #include <conio.h> using namespace std; void map1create(); // Function for creating the map1
I am getting the message Access violation reading location 0xccccccc8. when i try to print my dynamic array during the overloaded << function in my Flight class. where the error happens is surrounded by *s
In the code below. I believe I am returning the memory location of the value I am looking for. How can get the value?
main.cpp
int choice = 0; PlayerMenu *newPM = new PlayerMenu; File *file = new File; // Menu for loading, creating or exiting the game choice = newPM->menuChoices();
PlayerMenu.cpp
[Code] ....
I am not sure how to deference the value so I can get at the value instead of the memory location.
I found that the program works when using these values for the rows and columns:
Rows = 2; Cols = 2;
Using any other value gives the error mentioned above. It displays a small flat surface where I want it to, but I am trying to have a large enough surface to use as a ground (like 100 x 100).
I am getting an Unhandled exception at 0x00CB569E in AusitnHorton_Chapter17_7.exe: 0xC0000005: Access violation reading location 0xCCCCCCCC.
And, It puts a little yellow arrow at this line:
cout << nodepointer->value << " ";//print current node
when I try to run this program.
//Program:Make a ListNode and simple linked list class. Test the linked list class by adding varous numbers to the list and then test for membership. Then include a search function that returns the position of x on the list, if not found return -1.
I'm trying to make a menu object in SFML. So far all I've added is the ability to add buttons with text inside of them. I store the buttons in a vector and then loop through that vector to draw the buttons.
The error stems from line 24 of the 2nd piece of code.
Here's what I've got:
//MenuTest.h #include <SFML/Graphics.hpp> #include <string> #include <vector> class Menu1 { class Button1 { sf::RectangleShape body;
[Code] ....
This causes an error at the line window.draw(text); in Menu::Button::drawButton(). With the error "Access violation reading location (some memory address)".
Everything up to trying to draw the text works fine.
I would like to copy one bmp file to another using plain fstream (none 3-rd party library). I've managed to come up with something but I keep getting error:
Unhandled exception at 0x504A3442 (msvcr120d.dll) in ConsoleApplication1.exe: 0xC0000005: Access violation reading location 0x00380000.
when i try to write the content of the bmp files not the header, namely error occurs in this line:
Also i am not sure if i am doing it in a right way, meaning that even after solving this error i will copy the bmp file successfully.
Code:
// ConsoleApplication1.cpp : Defines the entry point for the console application. // #include "stdafx.h" #include <iostream> #include <fstream> using namespace std; struct BITMAPfileHEADER { unsigned short bfType;
I have a contiguous sequence of section headers in a file (all the data in the file is stored in void * data), where each section header is the same size and has the same fields in the same order. So it's laid out like an array.
I have to:
- Use an offset value and the number of section headers variables to identify the location and length of the section header table (these are hdr.offset and hdr.length respectively). - The offset value shows the distance between the start of the file and the start of the first section header (so I need a pointer to the start of the first section header) - Apply a typecast to location of the section header table to process it as an array of section headers.
Here is what I have done, but I am getting a segmentation fault. What am I doing wrong? How do I fix this?
typedef struct { unsigned int name; unsigned int type; } SectionHeader;
I am really desperate on trying to make my code work. The code is to find the eigen values of any given matrix of dimension NxN. The input can be the diagonal of any NxN matrix alongwith its subdiagonal. The code works fine for N~350 or so but when i go beyond that these errors appear.
First-chance exception at 0x00425ea4 in divide.exe: 0xC0000005: Access violation writing location 0x01141000. Unhandled exception at 0x00425ea4 in divide.exe: 0xC0000005: Access violation writing location 0x01141000.
But as i have never declared any variable statically and when i dynamically allocating memory with variables it should work like it does for smaller N values.
If I have a pointer variable indicating memory location in which we have stored what user entered and the pointer is of type volatile if the user gives the character 'a' twice , then this character will not be fetched twice from the memory but only when the character is changed???
This is the one meaning of the volatile? the other is that the value will be changed without the program itself change it?
I'm currently stuck whit a problem. I would like to access video memory of the console(Yes, only the black box) in C. I know how to do it in turbo pascal :
Var video:array[0..4000] of char absolute $B800:0000;
But i don't know the numbers in C. I've searched for the numbers of the memory in C but i can't find it.
I get a memory access violation when I run the below code. void createNewImage(int width, int height); this function deletes any current image data and creates a new image with the specified width/height and allocates the needed number of pixels dynamically. The new image contains four blocks with different color, red, blue, green, and black.
I am doing a project which I have to read, write and erase data from a NorFlash Memory. Then, I have to compare those data files in order to find errors.
Besides, I would like to know which is the best way to TEST errors in this kind of memories.
I am using NetBeans 7.3.1 for writting the code and Cygwin running on Windows XP Virtual Machine. The Memory Flash (S29JL064J 64 Megabit) is incorporated on an external board which is connected to an adapter board (using HDMI cable). This adapter is connected to the Laptop (using an USB).
I have CAN Dll program for my application,which was separately used.Now I have included the Drivers program into my application Program and I am having this error System Access Violation Exception:Attempted to read or write protected memory.i am attaching the Dll code and Application code which is throwing this error.
My Application Code which is the receiver thread for accessing the messages got onto the CAN bus.
DWORD WINAPI Rcv_Msg(LPVOID param){ int*MsgId = new int;//msg id from CAN intRcvVal;//0 = there is data in the queue; 1 = there is no data unsigned int uMsgId; *MsgId = 0; unsigned char CanData[8];
if we don't provide the acces modifiers for base class and we need to manipulate the private data of base class in derived class. Is there anyway to acces the private data members? Here's a coding example
class A { private : int a; }; class B : public class A { public : void displayA() { cout<<a<<endl; } };
how i can acces the a of base class A in derived class B without acces modifiers.
