I am working on a vc++ forms code. I need to get the current directory to open the help form of the project. While I tried all the code which I could find on internet everything as the same problem. I am posting one of the code below. The output of the code is true or false it is not returning the string which as a current directory value.
TCHAR pwd[MAX_PATH];
GetCurrentDirectory(MAX_PATH, pwd);
MessageBox::Show(Convert::ToString(&pwd), "My Application", MessageBoxButtons::OKCancel, MessageBoxIcon::Asterisk);
please help me out how to know the current directory in VC++ forms
You are passing the address of the pointer to Convert::ToString(). pwd is an array and using the variable name without an array subscript automatically decays to a pointer. You want to use either
Convert::ToString(pwd)
or
Convert::ToString(&pwd[0])
You are using C++/CLI. In that case, you should use .NET functions, whenevver possible... so instead of "GetCurrentDirectory" you should use the property System::Environment::CurrentDirectory!
Alternatively you should disable /clr (.NET) support and only use native functions!
If you really want to mix native and managed code, you should use the constructor for String to convert from TCHAR:
String^ str = gcnew String(pwd);
Related
We build an OCX that contains a Map control and many supporting classes (e.g. GeoProjection, Extents) which can act as standalone classes and many of which are also Properties of the Map.
One of our legacy applications that uses the OCX is built in Visual Basic 6. After updating the build from VS2013 to VS2015, we noticed differences in how we have to access some of the properties from VB6. The two in particular that we had problems with were the Map.GeoProjection and the Map.Extents properties. They both started raising "Library Not Registered" errors when attempting to use them.
In the case of the GeoProjection, I was able to resolve the problem simply by adding the VB 'Set' command to the assignment, as follows:
Dim gp As New GeoProjection
gp.ImportFromEPSG m_MapProjection ' contains the EPSG code
Set Map.GeoProjection = gp.Clone
Why the 'Set' wasn't required before this, I don't know. It seems like it should have been since it is setting an object reference.
Even so, when I tried to do the same with the Extents property, it did not resolve the problem, but instead resulted in an "Automation Error". So I next went to review the IDL and MFC macro definitions to see how the definitions differed and why the behavior might differ.
The GeoProjection IDL
[id(192)] IGeoProjection* GeoProjection;
end the Extents IDL
[id(17), propput, nonbrowsable] void Extents(IExtents* nNewValue);
[id(17), propget, nonbrowsable] IExtents* Extents();
The GeoProjection dispatch macro
DISP_PROPERTY_EX_ID(CMapView, "Projection", dispidProjection, GetGeoProjection, SetGeoProjection, VT_DISPATCH)
and the Extents dispatch macro
DISP_PROPERTY_EX(CMapView, "Extents", GetExtents, SetExtents, VT_DISPATCH)
What particularly struck me was the difference in using the DISP_PROPERTY_EX vs the DISP_PROPERTY_EX_ID. Ironically, I can find no Microsoft Documentation on DISP_PROPERTY_EX_ID. The only guidance I could find were comments in the afxdisp.h file, where it describes the two groups of macros, as follows:
on line 288, prior to the macros without the _ID suffix
// these DISP_ macros cause the framework to generate the DISPID
and on line 313, prior to the _ID suffixed macros
// these DISP_ macros allow the app to determine the DISPID
Since we have an .h file that defines dispatch IDs for every function, it seems that we should always use those IDs within the macros, as follows. This assures that the Dispatch IDs will always be the same (which I think would matter when using early-bound COM calls).
DISP_PROPERTY_EX_ID(CMapView, "Extents", dispidExtents, GetExtents, SetExtents, VT_DISPATCH)
Once I made changes to the Extents property in the IDL
[id(17)] IExtents* Extents;
and in the use of the DISP_PROPERTY_EX_ID macro, we were able to successfully set the Extents property from VB6 using the 'Set' statement.
In summary, I don't really know
why the behavior changed in the first place (from VS2013 to VS2015)?
why my changes made things start working again (I have my theories)?
what is the recommended methodology going forward?
a. IDL syntax allows for property definition without having to specify propput and propget. Is one syntax recommended over the other?
b. should I change all of our macros to use the _ID suffixed macro?
Any insight is appreciated.
Thank you.
I'm trying to write a plugin for 3ds max, I went through the entire sdk installation process to the letter as described in the help files.
The problem I'm facing though is intellisence complaining about an invalid macro definition
"IntelliSense: command-line error: invalid macro definition:_CRT_SECURE_CPP_OVERLOAD_STANDARD_NAMES_COUNT =1"
I found the definition in project settigs -> c/c++ -> preprocessor definitions as inherited from parent or project default.
I tried disabling the inherited definitions and re-entered them, this time without the space between the name and the = and all works fine so I'm guessing its a typo on their part?
Anyway, I want to change the default project or whatever to not repeat it every time i start a new project. The project is created with a wizard which required me to copy over some files to appear and after which I had to enter the sdk path.
The files I copied are plain text with some fancy extensions and not much in them so I'm guessing the defaults are described in the sdk directory.. somewhere. Does anybody know what kind of a file I'm looking for?
EDIT: I found a file called root.vcxproj_template and it has a section for preprocessor definitions but all it contains is
<PreprocessorDefinitions>_USRDLL;%(PreprocessorDefinitions)</PreprocessorDefinitions>
and no mention of the broken one
EDIT2: in another part of the file there was a path to a property sheet (maxsdk\ProjectSettings\propertySheets\3dsmax.common.tools.settings) which included the faulty definition. I fixed it an no more complaints from VS.
_CRT_SECURE_CPP_OVERLOAD_STANDARD_NAMES_COUNT = 1 means that compiler should replace all old C run-time routines such as sprintf, strcpy, strtok with new versions such as strprintf_s, strcpy_s, strtok_s and similar. It goes in pair with following definition _CRT_SECURE_CPP_OVERLOAD_STANDARD_NAMES = 1.
More you can find here: (MSDN) https://msdn.microsoft.com/en-us/library/ms175759.aspx. However I tried to use this but without success. It says that you can use this only for statically allocated buffers like char buffer[32], but compilers was still complaining bout unsecure strcpy.
Sorry about the short title, but I honestly can't get a better description of what is happening because I don't know enough...
Some background first, I am "converting" a multi-byte application to support unicode and I've made the standard char/string wchar_t/wstring changes and the my code is building without problems.
What happens is that when the application is being initialized it hits an assert when it registers the applications's document templates. The code is the standard
CMultiDocTemplate* pRepDocTemplate = NULL;
pRepDocTemplate = new CMultiDocTemplate(IDR_DIAGNOSTIC_REPORT_TYPE,
RUNTIME_CLASS(CDiagnosticReportDoc),
RUNTIME_CLASS(CChildFrame), // custom MDI child frame
RUNTIME_CLASS(CDiagnosticReportView));
and CDiagnosticsReportView has the standard DECLARE_DYNCREATE and IMPLEMENT_DYNCREATE in the header and source.
The assert is at doctmpl.cpp line 29 (mfc120ud.dll - at least is using the correct dll), but I can't find the source code anywhere to actually know what is happening.
The inheritance tree is pretty straightforward:
CDiagnosticReportView
\->CReportViewBase
\->CXTPReportView
\->CView
CXTPReportView is part of a framework that we are using which is provided by Codejock (Codejock extreme toolkitPro). From the build pane I know that it's linking against it's unicode debug dll (ToolkitPro1631vc120UD.dll)
Suffice to say that in the multibyte configuration this problem doesn't occur.
The project is configured to use the UNICODE character set (Project properties->Configuration Properties->General->Character Set).
Any help would be appreciated!
Thanks in advance!
It all had to do with the fact that I was linking against the non UNICODE build of Codejock. Even though I saw a reference to the UNICODE dll, the lib wasn't the correct one!
Problem was solved when I opened my eyes ;)
i am trying to Print some data in wxstring using printf function but its crashing in run time in LINUX but not in windows
here is my code:
wxString str1,str2;
str1 = "Elements";
str2.Printf( _U("%s"),str1);
This is working in windows but not in linux , if i change it below its working in linux also
str2.Printf( _U("%s"),str1.c_str());
why its not taking str1 as argument.
Note:This sentence i am using throughout the workspace is there any common way to do this in linux instead of changing in all places
The only "fix" is to upgrade to wxWidgets 3.0 where wxString::Printf() and other similar functions are (pseudo) variadic templates and so do work correctly with objects and not only raw pointers. In wxWidgets 2.8 they are variadic functions and, according to the language rules, can't work with the objects and no, there is no way around this.
This help clarify you:
The following code:
wxString str;
str.Printf(wxT("My string is %s"), wxString("whatever"));
does not work. Unfortunately, it may seem to work fine under Windows because of a compiler quirk there but passing a wxString object to a function taking a variable number of arguments such as Printf() is undefined behaviour in C++. Accordingly, it will simply crash under most platforms but may even "work" on some of them.
You must use c_str() to make the above code work, i.e. write this instead:
wxString str;
str.Printf(wxT("My string is %s"), wxString("whatever").c_str());
Note that g++ should give you an error when passing an object to a vararg function like this -- another reason to compile your code with g++ even if you normally use another compiler.
After building in Release mode, I am seeing exceptions which didn't occur in Debug mode. When debugging the release build, it looks like string references are not being passed correctly from the EXE (our application) to the DLL which is receiving the string reference.
Our EXE code looks like this:
string contents = "handle_message(): received=" + msg->encode();
LOG4CXX_DEBUG(logger, contents);
The LOG4CXX_DEBUG is going to log4cxx.dll, whose code looks like this:
CharMessageBuffer& CharMessageBuffer::operator<<(const std::basic_string<char>& msg) {
if (stream == 0) {
buf.append(msg);
} else {
*stream << msg;
}
return *this;
}
Looking at the Call Stack in the debugger, when I navigate down to the frame which has our source, I can see that contents is a valid string with size=583, capacity=838.
In the frame inside the log4cxx.dll (the next frame above in the stack) the string reference shows size=838, capacity=363113231 (and the values are all garbage).
Both our app and log4cxx.dll were compiled on the same machine, using the same runtime settings (/MD), but different versions of Visual Studio. The log4cxx dll was compiled using Visual Studio 2008 and our application was compiled using Visual Studio 2010. Running dumpbin on the 2 objects shows:
Our App (EXE)
MSVCP100.dll
MSVCR100.dll
log4cxx.dll (DLL)
MSVCP90.dll
MSVCR90.dll
Is this problem due to the fact that they are using different runtime versions?
If you pass non-POD (plain old datatypes) between DLL/EXE boundaries (like STL string or CRT FILE pointers) you must use the same shared CRT.
In your case, you must recompile all DLLs/LIBs with the same compiler!
See also: I can pass std::string for a Dll and what i can do with DLL´s?
The implicit question is:"Is there a way to pass data, hopefully using string and other STL containers, to DLLs of another version of visual studio either previous or later than the one that I'm using?".
Aside from using POD, there are probably three approaches: shared memory, sockets( to local host ) and MSMQ. All of these methods require additional extensive programming, but the deeper answer is found in how the interface is changing the input parameter.
I have found a possible solution to the string passing problem on the internet. It removes one layer of corruption; cast a pointer to the container to a uint and pass the uint. Dereference the uint to the pointer and the object is revealed. Beware, auto_ptrs are usually deleted in this process, so don't use them. If the passed object is still offset incorrectly( this happened to me with VS08 passing to a VS13 ), then pass the c_str() of the string instead. It's certainly inelegant, but we need to know all the alternatives. See "HowTo: Export C++ classes from a DLL" in Code Project( Nov 22, 2012 ).