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First let me say you are making a mountain out of a molehill ... "test->" is a dead easy string to pick off with a text auto-replace on. Would take me about 30sec to do on code throughout the project.
You could also do what a good programmer would do and get rid of the stupid global pointer and pass it into the functions on the local interface. You can keep it as test on the local interface but pass in lets_use_it.test1. You make your code better, safer and it is simply extending a few local interfaces. That is what I would actually do .. globals are evil 
The question to ask yourself is why are you using the global pointer rather than having a pointer parameter on the functions that use the global?
That all said you could keep the pointer "as is" if you want by typecasting but it is frowned on 
struct test1* test = lets_use_it.test1;
In vino veritas
modified 16-Jun-17 10:22am.
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We have a console application in VS2008 in which we have defined a global variable for a structure. The members of the variable are used throughout the application in various functions.
Recently we have taken some of the functions out of the application to create a separate library and have included the library and the header file in the console application.
Now When I build the application and run it, the output and behavior of the whole application is correct and same as before. But when i try to set breakpoints and debug some of the functions in the console application to watch the values in the watch window, the structure variable shows empty in the value column. The global variable for the structure is also used in the library.
Please suggest a solution to view the values in the watch window
modified 12-Jun-17 7:41am.
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Check the project settings and ensure that both the application and library are built in Debug mode.
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Problem solved. One of the lib was in release mode. got it fixed. Thanks
modified 13-Jun-17 3:38am.
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That should work and does on VS2015 and VS2107 so if it doesn't work on VS2008 it's a very old bug.
You can however easily hack around it, just make a local variable struct and copy the global struct to the local ... the watch window can't get that wrong and it's one single line of code
Other alternative is to try the later compilers, they are free and easy to download and try.
In vino veritas
modified 13-Jun-17 3:04am.
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Hey all,
When you save a webpage, eg from firefox "Web page, complete", it saves an html file and a folder containing its resources. No problem. But the tricky bit is, you move/copy/delete the html file the resource folder does the same.
How do they do that!?? I'm guessing there is some shell extension, but the only thing close I find in MSDN is ICopyHook, which seems more like a proceed/abort confirmation.
Thoughts?
(and dare I ask...) Examples?
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It is a Windows shell feature called Connected Files[^] and applies only to HTML files (*.htm, *.html).
If you want an application to use that feature it must use shell file operations (SHFileOperation function (Windows)[^], IFileOperation interface (Windows)[^] ) instead of Windows API file operations.
I don't know for sure how it is implemented but I guess that it just checks for the existance of matching directories for HTML files and vice versa for directories with the listed extension.
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The HTML filename is used to create the associated directory, so they are connected by name.
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Hello!I'm trying to disable a text box (named m_EarthPermeability) and I want to disable it if a certain value is in Combobox (named m_Layers which gets two values "1" and "2"). Both textbox and Combobox are on the same Dialog window. I have written the code below but the textbox is still in "use" after choosing value "2" in Combobox. Here is the code:
CInputView::CInputView()
: m_Layers(0)
, m_EarthPermeability(0)
void CInputView::OnLinefeaturesFeatures()
{
CInputDoc* pDoc = GetDocument();
CFeaturesDialog DialogWindow;
DialogWindow.m_DialogLayers = m_Layers;
DialogWindow.m_DialogEarthPermeability = m_EarthPermeability;
{
if (m_Layers == 2) {
GetDlgItem(IDC_Permeability)->EnableWindow(FALSE);
}
}
modified 8-Jun-17 5:33am.
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To disable a control you have to call EnableWindow(FALSE) but in your code snippet you are passing TRUE.
I understand also that the text box is part of the dialog and not of your view. Then you have to use
if (m_Layers == 2) {
DialogWindow.GetDlgItem(IDC_Permeability)->EnableWindow(FALSE);
}
It is also not clear if the member variables of your dialog are controls (CEdit, CComboBox) or values (CString, int). Your code is correct for value types but not for control types (which is indicated by "a text box (named m_EarthPermeability)").
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I changed the errors you mentioned but still didn't work. So I made some more changes concerning the combobox but didn't work either. Here is the code:
void CInputView::OnLinefeaturesFeatures()
{
CInputDoc* pDoc = GetDocument();
CFeaturesDialog DialogWindow;
CString buffer;
buffer.Format(L"%d", m_Layers);
DialogWindow.m_DialogLayers = buffer;
DialogWindow.m_DialogEarthPermeability2 = m_EarthPermeability;
if (m_Layers == 2) {
DialogWindow.GetDlgItem(IDC_EarthPermeability2)->EnableWindow(FALSE);
}
}
where m_DialogLayers is CString type and its control type is combobox. Variable m_Layers is int variable.
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It can not work that way because the dialog is not shown so far. Before you can change the visibility of a dialog's control you must show the dialog using DoModal() (for a modal dialog) or Create() and ShowWindow() (for a modeless dialog).
But your general approach is wrong. You should put the code to disable the control into the dialog class. Do it there in OnInitDialog() for the initial display and into handlers upon changings (e.g. by handling the CBN_SELCHANGE notification code (Windows)[^] )
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Could you please give me some more information on how to use CBN_SELCHANGE cause I am not very familiar with that. You mean to use it in OnInitDialog()?I tried different cases but still didn't manage to make it work. Thank you in advance for your time and help!!
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In your view you create an instance of the dialog, set the members for the control as already done and finally call DoModal() to show the dialog (I will not handle modeless dialogs here).
When having a modal dialog the default implementation of OnInitDialog() will call CWnd::UpdateData[^] to set the controls from the corresponding member variables. Override OnInitDialog() to do additional initialisation:
BOOL CFeaturesDialog::OnInitDialog()
{
BOOL bRet = CDialog::OnInitDialog();
if (m_DialogLayers == 2)
GetDlgItem(IDC_Permeability)->EnableWindow(FALSE);
return bRet;
}
If you want to enable/disable the control when the user changes the combo box selection, you have to add a corresponding handler. Open the dialog resource in the resource editor, right click on the combo box to open the context menu and select the option to add a handler. That will open a dialog that allows you to choose the notification. Select CBN_SELCHANGE and apply the settings. That will create a function declaration in the header file, a function body in the source file, and open the source file at the created function. See also Adding an MFC Message Handler[^]. You should become familiar with that because you have to use it frequently with MFC applications.
In your case get the pointer to the control and use that to get the index (untested):
CFeaturesDialog::OnCbnSelchange()
{
CComboBox *pCombo = (CComboBox*)GetDlgItem(IDC_LAYERS);
GetDlgItem(IDC_Permeability)->EnableWindow(pCombo->GetCurSel() != 2);
}
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I saw here:
Flicker Free Drawing In MFC[^]
in MemDC source code a line:
CMemDC* operator->()
{
return this;
}
Sorry for this simple question: it was really necessary ?
If I have an already pointer to an CMemDC object, and I write pMemDC->, then is not the same thing like this operator didn't has been overloaded ?
Thank you for any clarifying !
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It is the same if you already have a pointer. But that class is usually created as
CMemDC pDC(dc); where you don't have a pointer.
The reason for the overload is that the class is used instead of the CDC* which is passed to the drawing functions. So you can modify existing code for the CDC* by just replacing the variable name without changing the access operator from -> to ..
Using such is bad practice but has been used by MFC too. It makes sense for this special class but should be generally avoided.
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I think I can help but I am struggling with the grammar and intent of your question. -> operator gives you access to the class. It is much like operator .
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I was reading this article, and I'm trying to understand a point that the author is trying to make.
Bartek's coding blog: Smart pointers gotchas[^]
class Test
{
public:
Test():m_value(0) { std::cout << "Test::Test" << std::endl; }
~Test() { std::cout << "Test::~Test destructor" << std::endl; }
int m_value;
};
typedef std::auto_ptr<test> TestAutoPtr;
typedef std::unique_ptr<test> TestUniquePtr;
typedef std::shared_ptr<test> TestSharedPtr;
void doSomethig(TestAutoPtr myPtr) {
myPtr->m_value = 11;
}
void AutoPtrTest() {
TestAutoPtr myTest(new Test());
doSomethig(myTest);
myTest->m_value = 10;
}
The author says this will crash. It seems that when myTest is instantiated, there is an auto_ptr object that now exists as a member of myTest, pointing to a heap instantiation of Test. Then when doSomethig() is called the *value* of the pointer is passed (i.e., the address of that heap Test object), and a new auto_ptr object, myPtr, is created, with its value set to the address of that Test object. And then after doSomethig() finishes, myPtr is destroyed, but since it is an auto_ptr, that destruction will delete the object that has the address of its value (i.e., the Test object). So, when a dereference of the myTest object (i.e., an auto_ptr object) is attempted, the Test object is no longer there, and hence an error that is as per trying to dereference an uninitialized (or perhaps null?) pointer.
Is my explanation accurate?
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Close but not quite the actual rule goes
An auto_ptr owns the thing/object that it holds a pointer to, and only one auto_ptr may own an object at a time. When you copy an auto_ptr, you automatically transfer ownership from the source auto_ptr to the target auto_ptr. After the copy, only the target auto_ptr owns the pointer and will delete it in due time, while the source is set back to a null state and can no longer be used to refer to the owned object.
The line
doSomething(myTest);
has an implicit copy because you passed in myTest so the ownership goes into doSomething (passing like that is called an auto_ptr sink operation) and myTest gets the null state as per the description. You can't use it afterwards because it got nulled so it's a guaranteed crash if you try to use the pointer.
If you want the auto-pointer back again you should have made doSomething a function returning an auto_ptr and passed it back out, try something like
TestAutoPtr doSomethig(TestAutoPtr myPtr) {
myPtr->m_value = 11;
return myPtr;
}
The higher level code becomes
void AutoPtrTest() {
TestAutoPtr myTest(new Test());
myTest = doSomethig(myTest);
myTest->m_value = 10;
}
It's just an ownership thing .. only one scope of code can own an autoptr. If you want it back again you need to pass it back otherwise it is assumed it is no longer in use and cleaned up.
The actual crash has nothing to do with the cleanup the null of the auto_ptr is automatic when it copied and it's that which causes the crash. You are attributing the crash to the cleanup which isn't the case. If you could somehow keep the autoptr inside doSomething alive say with multitask code you still couldn't use the original pointer because it's value will be null.
Just use the debugger put a breakpoint on doSomething and single step into it and look at what happens to the original pointer .. your toast from that point on with the original code because it will go to null
In vino veritas
modified 6-Jun-17 16:10pm.
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Hi
I have been trying to build the assimp library (a open source library to load 3d models) using my visual c++ 2008 compiler and cmake. I read a number of websites, tried various methods, but nothing seems to work. I managed to get cmake to generate a workspace but compiling gives hundreds of errors. Anybody know how to build assimp under visual studio? Any help appriciated.
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You first need to look at the compiler errors and figure out what is wrong in the build. Or go back to the source and see if there is any documentation that will help.
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This'll probably do it:
https://github.com/assimp/assimp-net
Go there and download the AssimpNet.sln container called "assimp-net-master.zip". I looked at the assimp GITHUB project just now and noted a whole cockpit full of nonsensical info about CMAKE .. and roughly recall confusing CMAKE with some MS utility of a by-gone era using the suffix "MAKE" but I don't think this is a star in anybody's forest so don't bother reading further there.
Hope this helps.
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Resolution: In the environment variables for include and lib there were three copies of one directory. That lead to the deletion of some other items. I suspect those three copies were the results of multiple upgrades and installs beginning with VS 2005.
Windows 7, visual Studio 2010, C++, MFC
I posted this on MDSD a week ago and have no replies. The essence is that definitions from within Visual Studio are showing up as being redefined. I do not have direct control over these and cannot find the indirect control / problem / defect that I have managed to insert in the code.
Here is the first of a long list of errors in the Output window
1>c:\program files\microsoft visual studio 9.0\vc\include\codeanalysis\
sourceannotations.h(57) error c2011:
'vc_attributes::YesNoMaybe' : 'enum' type redefinition
First, I cannot copy/paste from my working computer to my internet computer so please excuse any typos. If you see one, feel free to mention it as there may be an error, but please do not reject everything out of hand due to typos.
I searched for this problem and found several results, including an unanswered question from 2008 here:
https://social.msdn.microsoft.com/Forums/en-US/fb887af6-45dc-42b9-94bb-ab4d08a16dd8/64bit-compiler-error?forum=Vsexpressvc
It included advice to clean and rebuild. Following said advice I did a “Clean.” Then I closed Visual Studio entirely and ran a batch file I have named clean.bat that deletes 14 types of files in the solution directory and all subdirectories followed by a rebuild. A restart of VS and a build produces the same problem.
The titular error and similar errors are repeated numerous times.
Edit: to complete the title the entire error is (with a couple of CRs added for readibility:
1> winnocc.cpp
1>c:\program files\microsoft visual studio 9.0\vc\include\codeanalysis\
sourceannotations.h(57) error c2011:
'vc_attributes::YesNoMaybe' : 'enum' type redefinition
Much further down in the error list is found:
… message_constants.h(50): error C2370: ‘NO_NAME_SPECIFIED’ : redefinition; different storage class
That particular file begins with
#pragma once
The constant is referenced one time only in the entire project, and that reference is within the same file.
So,…, I surmise that the #pragma once is not working. Maybe I did something to defeat it, I don’t know.
So, …, I added these lines to the start of the file, just below the pragma once
#ifndef MESSAGE_CONSTANTS
#define MESSAGE_CONSTANTS
… entire file contents …
#end if
Then, just to be certain, in every file that references this file I added these lines just above and below the include
#ifndef MESSAGE_CONSTANTS
#include message_constants.h
#endif
Question: What have I done wrong to incur such wrath upon myself?
Edit 2 hours after initial post
While trying to chase down this problem I discovered that the file name is really Message_Constants.h. When I chase down the error the file name at the top of the edit windows shows the name "message_constants.h" It also shows "Message_Constants.h" What is with the all lower case versus the leading caps?
I execute a Save As to ascertain the actual location and it is as expected. Open Windows explorer and it finds "Message_Constants.h and it does not find "message_constants.h" Now I have changed all occurrences to use the leading caps version but this problem remains.
Edit Again
I looked at file sourceannotations.h and found #pragma once. So I added the standard guard macros as presented earlier and they made no difference.
Monday, 22 May Edit
I added the /showIncludes options. Below is the lead in to the first error message. Again, I cannot cut paste so a few typos may be present. And just in case it might be significant: Where I wrote (indented here) means that that line was indented in my output window but this system is not showing an indentation.
Each line is prefixed with the two characters: 1>. None progress to 2>
Quote:
C1compile
All outputs are up-to-date.
stdafx.cpp
winocc.cpp
Note: including file: C:\Program Files Microsoft Visual Studio 9.0\VC\atlmfc\src\mfc\occimpl.h
Note: including file: C:\Program Files Microsoft Visual Studio 10.0\VC\atlmfc\include\atldbcli.h
Note: including file: C:\Program Files Microsoft Visual Studio v7.0A\include\oledberr.h
Note: including file: C:\Program Files Microsoft Visual Studio v7.0A\include\msdaguid.h
Note: including file: C:\Program Files Microsoft Visual Studio v7.0A\include\msdasc.h
Note: including file: C:\Program Files Microsoft Visual Studio 9.0\VC\include\sal.h
Note: including file: C:\Program Files Microsoft Visual Studio 9.0\VC\include\codeanalysis\sourceannotations.h
c:\program files\Microsoft visual studio 9.0\vc\include\codeanalysis\sourceannotations.h(57): error c2011: 'vc_attributes::YesNoMaybe' : 'enum' type redefinition
(indented here) c:\program files\Microsoft visual studio 10.0\vc\include\codeanalysis\sourceannotations.h(57) " see declaration of 'vc_attributes:: YesNoMaybe'
Thank you for your time
modified 22-May-17 17:55pm.
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