I'm using Visual C++ to build and test a project, but I'll also be using it on other platforms. I started the code initially on a different platform.
In some of my class headers I need to include a file which is specific to the other platform, however, this file doesn't exist in the Visual C++ workspace.
I've tried using code like this:
#if TARGET == OTHERPLATFORM
#include "themissingfile.h"
#endif
where TARGET is defined elsewhere as WINDOWS
#define TARGET WINDOWS
However, I still get a compiler error stating that "themissingfile.h" cannot be found. It appears like the precompiler is processing the include before the if. What's the best way to get around this? I suppose I could just create a blank "themissingfile.h" in the Visual C++ source folder, but it seems to me like there should be a better solution.
#define TARGET WINDOWS does not set TARGET to the string WINDOWS: it sets it to whatever WINDOWS is defined to. Most likely this happens:
#define WINDOWS // Sets WINDOWS to 0
#define OTHERPLATFORM // Sets OTHERPLATFORM to 0
#define TARGET WINDOWS // Sets TARGET to 0
#if TARGET == OTHERPLATFORM // Evaluates to 0==0, so true
Use _WIN32 macro instead:
#ifndef _WIN32
#include "themissingfile.h"
#endif
_WIN32 is defined for both 32-bit and 64-bit builds. See C/C++ Predefined Macros.
Related
I have a VS (C++) project that relies on OpenCV and TBB, so I created property sheets for each library and included them in the project. Everything worked fine and the code compiled.
Yesterday, I have started using vcpkg package manager. I installed OpenCV and TBB via vcpkg and everything seemed to work. I created an empty project, included the headers of both and tested if the new compiled libraries work. After verifying that, I went back to my main project and removed the property sheets, so I can use the libraries from vcpkg. I did not change the code in any way since the last successful compilation.
But when I try to compile the code now I get this error two times (in main.cpp and in a submodule)
tbb\critical_section.h(53): error C3861: 'InitializeCriticalSectionEx': identifier not found
Does anybody know what is going on here or why this error occurs?
Update
I found the error myself. I'm adding the poco-libraries tag, because it's actually a conflict between TBB and Poco.
I found the source of the problem and it has actually nothing to do with TBB but with the Poco library.
Consider the minimum example:
#include <Poco/Poco.h>
#include <tbb/tbb.h>
void main()
{
}
This will throw an compiler error.
Tracing down the path
When including tbb.h, critical_section.h is included in line 51 of tbb.h. However, ciritcal_section.hpp includes machine/winwdows_api.h which looks like this (unnecessary stuff is cut out):
tbb/machine/winwdows_api.h:
#if _WIN32 || _WIN64
#include <windows.h>
#if _WIN32_WINNT < 0x0600
#define InitializeCriticalSectionEx inlineInitializeCriticalSectionEx
inline BOOL WINAPI inlineInitializeCriticalSectionEx( LPCRITICAL_SECTION lpCriticalSection, DWORD dwSpinCount, DWORD )
{
return InitializeCriticalSectionAndSpinCount( lpCriticalSection, dwSpinCount );
}
#endif
As you can see, windows.h is included before the check of the _WIN32_WINNT macro. This macro is defined in sdkddkver.h (which is included in windows.h), iff it's not already defined (in my case it's set to Win10):
sdkddkver.h:
#if !defined(_WIN32_WINNT) && !defined(_CHICAGO_)
#define _WIN32_WINNT 0x0A00
#endif
In windows.h, the _WIN32_WINNT macro controls which version of the windows header files are actually included. If _WIN32_WINNT is set to an earlier version than Windows Vista, the function InitializeCriticalSectionEx is not defined.
This issue is catched by machine/winwdows_api.h (as you can see in the code block of that file) by simply defining a macro InitializeCriticalSectionEx that calls an appropriate alternative function.
So far so good.
The problem
The root of all evil lies in Poco/UnWindows.h of the Poco library. When including a poco header, at some point UnWindows.h will be included.
Poco/UnWindows.h (shortened):
#if defined(_WIN32_WINNT)
#if (_WIN32_WINNT < 0x0501)
#error Unsupported Windows version.
#endif
#elif defined(NTDDI_VERSION)
#if (NTDDI_VERSION < 0x05010100)
#error Unsupported Windows version.
#endif
#elif !defined(_WIN32_WINNT)
#define _WIN32_WINNT 0x0501
#define NTDDI_VERSION 0x05010100
#endif
#endif
#include <windows.h>
The preprocessor checks, if _WIN32_WINNT is already defined, and if not, sets it to 0x0501 which is Windows XP. After that, windows.h is included. In the previous chapter I mentioned that _WIN32_WINNT controls which version of the windows header files are actually included.
Now imagine, the very first include in our project is a header from Poco. This means, that _WIN32_WINNT will be set to Windows XP and windows.h will include the windows headers of Windows XP (which imo is already a bad sign).
But don't worry, it gets worse.
If we trace the include hierarchy one level up, we reach Poco/Platform_WIN32.h.
Poco/Platform_WIN32.h (shortened):
#include "Poco/UnWindows.h"
...
#if defined (_WIN32_WINNT_WINBLUE)
#ifdef _WIN32_WINNT
#undef _WIN32_WINNT
#endif
#define _WIN32_WINNT _WIN32_WINNT_WINBLUE
...
Funny, isn't it? First, it includes UnWindows.h, which sets _WIN32_WINNT and causes Windows XP headers to be included, and next it redefines _WIN32_WINNT to be Windows 8.1. I have no clue why it does that, maybe there is a good reason, idk.
If we now look at the minimum example at the very top we see that Poco is included before TBB. What now happens is:
Include Poco headers
Set _WIN32_WINNT to Windows XP
Include windows headers (Windows XP version, because of 2)
Reset _WIN32_WINNT to Windows 8.1
Include TBB headers (windows headers are already included, so TBB doesn't need to include them again in tbb/windows_api.h)
TBB checks the windows version via _WIN32_WINNT and recognizes Windows 8.1 (as set by Poco)
TBB thinks InitializeCriticalSectionEx is defined, because the Windows version is 8.1 (or is it? Poco says: get rekt) and InitializeCriticalSectionEx is defined since Windows Vista.
Unfortunately Poco ensured that the Windows XP headers are loaded, so compiler says: no.
The solution
Either include windows.h yourself beforehand, or set _WIN32_WINNT yourself beforehand:
#define _WIN32_WINNT 0x0A00 // either this
#include <Windows.h> // or this
#include <Poco/Poco.h>
#include <tbb/tbb.h>
void main()
{
}
Maybe someone of the Poco contributors can clarify some things here. The Poco version is 1.8.1-1 built with x64 (via vcpkg).
Update
Poco is on the issue. Updates can be found here.
I tried to compile TBB which I want to use on OpenCV. I am using Windows XP and Visual Studio 2010 C++. When I compiled TBB 4.4 I got the error
"The procedure entry point InitializeCriticalSectionEx could not be located in the dynamic link library KERNEL32.dll."
The error is similar but under little different conditions like here:
http://answers.opencv.org/question/6151/opencv_createsamplesexe-entry-point-problem-with-xp/
In my case I cannot run the program at all. I tried the solution described there, so I renamed InitializeCriticalSectionEx to InitializeCriticalSection and removed parameter 2 and 3.
OpenCV claimes the bug is not on their side. I know OpenCV uses this:
#if (_WIN32_WINNT >= 0x0600)
InitializeCriticalSectionEx(&cs, 1000, 0);
#else
InitializeCriticalSection(&cs);
#endif
I know this should not make any problems but I commented some lines to keep InitializeCriticalSection(&cs); only. I recompiled the OpenCV and still the same error. Finally I have found in TTB:
tbb44_20160627oss\include\tbb\machine\windows_api.h
__TBB_WINBASEAPI BOOL WINAPI TryEnterCriticalSection( LPCRITICAL_SECTION );
__TBB_WINBASEAPI BOOL WINAPI InitializeCriticalSectionAndSpinCount( LPCRITICAL_SECTION, DWORD );
// Overloading WINBASEAPI macro and using local functions missing in Windows XP/2003
#define InitializeCriticalSectionEx inlineInitializeCriticalSectionEx
I also find the word "InitializeCriticalSectionEx" in opencv_core310d.dll and opencv_core310.dll. Does the overload really work and why I got the error? How could I fix it?
Update:
the definition in OpenCV
#ifndef _WIN32_WINNT // This is needed for the declaration of TryEnterCriticalSection in winbase.h with Visual Studio 2005 (and older?)
#define _WIN32_WINNT 0x0400 // http://msdn.microsoft.com/en-us/library/ms686857(VS.85).aspx
#endif
"The procedure entry point InitializeCriticalSectionEx could not be located in the dynamic link library KERNEL32.dll."
This is a standard error that Windows displays when you try to run a program that contains a statically-bound call to a function in a DLL that does not exist.
The InitializeCriticalSectionEx function is not available on Windows XP, but the version of the library that you have contains code that calls this function.
OpenCV claimes the bug is not on their side. I know OpenCV uses this:
#if (_WIN32_WINNT >= 0x0600)
InitializeCriticalSectionEx(&cs, 1000, 0);
#else
InitializeCriticalSection(&cs);
#endif
OpenCV's workaround is a compile-time solution. It determines at the point when the library is compiled which version of Windows is being targeted, and uses that information to generate a call to the appropriate version of the function.
There are two possibilities for why this is going wrong in your case:
You are using the OpenCV library in binary form, and the binary that you have was compiled to target Windows Vista and later. You can solve this by obtaining the source code for OpenCV and compiling it yourself, either as a DLL or a static library.
You are compiling with _WIN32_WINNT set to 0x0600 or later. By default, the Windows headers define this symbol to the latest available version. You have to explicitly define an earlier target version if you want it. To arrange for targeting Windows XP, add the following code at the top of your code file (probably in your precompiled header):
#include <WinSDKVer.h>
#define _WIN32_WINNT _WIN32_WINNT_WINXP
#include <SDKDDKVer.h>
EDIT 2: Ok so I changed to Orwell DevC++ which contains the "winnt.h" that contains #define KEY_WOW64_64KEY 0x0100 but it still is not working. (Refer to EDIT 1:)
EDIT 1: I looked into the "winnt.h" which came along the CodeBlock and DevC++ and the DevC++'s is missing the following lines:
#if (_WIN32_WINNT >= 0x0502)
#define KEY_WOW64_64KEY 0x0100
#define KEY_WOW64_32KEY 0x0200
#endif
And putting the above code in the wint.h of DevC++ doesn't work.
Original Post:
I have a 32bit application (developing in DevC++ and Windows 7 64bit) which reads a 64bit app's registry as one of its task, so I am trying to use "KEY_WOW64_64KEY" flag in RegOpenKeyEx, and found few posts regarding how to use it with _WIN32_WINNT : this and this
It worked like charm when I used it in a CodeBlock Project(a test project) but the same code is not working with DevC++, I can't port it to codeblock now since codeblock presents other problems.
How do I make it work with DevC++ ?
Thanks
It defines the version of the windows header files to use. It must be declared before you #include <Windows.h>.
There are a few other similar variables you should probably set if you're going to modify it:
MSDN Using Windows Headers
_WIN32_WINNT is a preprocessor token, which is replaced by (0x0601) wherever _WIN32_WINNT is used. The preprocessor just scans the whole file and replaces _WIN32_WINNT with (0x0601) everywhere it is found.
Chances are, there could be ifdef preprocessor guards that will enable/disable a preprocessor constant. Like:
#ifdef _WIN32_WINNT
#define KEY32 32
#endif
There, KEY32 will only be defined IF _WIN32_WINNT is defined.
It already works with DevC++.
I am trying to migrate existing c++ 32 code to 64 code on windows7 with visual studio 2010.i never did 64bit compilation before. with the help of internet references i did the setup for 64 bit compilation. like VS2010 with 64 bit compiler etc and other configuration changes.
In the preprocessor i removed WIN32 and added WIN64. i have some other pre-processors like OS_WIN_32 and some other which are specific in my code.
In the code wherever WIN32 was getting used i added extra condition as || WIN64 this is just to ensure that application should get compiled with win32 as well as win64.
When i am trying to compile the code i am getting the compilation error saying
fatal error C1189: #error : Only one of the WIN32 and WIN64 symbols should be defined
this error is coming from the local code where we have a check whether both WIN32 and WIN64 are defined. that code is as shown below.
#if defined WIN32 && defined WIN64
# error Only one of the WIN32 and WIN64 symbols should be defined
#endif
in VS2010 if macros are not enabled then the code inside the macro gets greyed out. in my code also the above error is greyed out. but still i am getting that error.
The code where i added WIN64 is including windows.h. for reference givine it below.
#if defined WIN32 || defined WIN64
#include <windows.h>
#include <process.h>
#endif
So my question is why i am getting this error? shouldnt we add windows.h for 64bit compilation.? i tried by commenting this inclusion but i am getting other errors wrt HANDLE which are used in the code.
If i go to WIN32 definition VS2010 is pointing to a definition in windef.h file. This file is present in Microsoft SDKs\windows\v7.0A\include folder i.e. not my local code.
for referance that definition is given below.
#ifndef WIN32
#define WIN32
#endif
So i want to know why compiler is getting both pre-processors WIN32 and WIN64.
Thanks in advance for your help.
You shouldn't define either yourself. The macro's that should be used to check this are
_WIN32 // always defined for Windows apps
_WIN64 // only defined for x64 compilation
These are defined by the compiler (see here).
Often, the IDE adds the unprefixed macros to the commandline to not let legacy projects which use the non-documented unprefixed versions fail to build. The fact that they work is not a reason to use them, when documented alternatives are present.
It boils down to this:
#ifdef _WIN32
// We're on Windows, yay!
#ifdef _WIN64
// We're on x64! Yay!
#else // _WIN64
// We're on x86 (or perhaps IA64, but that one doesn't matter anymore). Yay!
#endif // _WIN64
#else // _WIN32
// We're not on Windows, maybe WindowsCE or WindowsPhone stuff, otherwise some other platform
#endif
I'm compiling my application on a new box (vista 64) and now it doesn't compile anymore. The compiler gives me the error in the title. The problem seems(?) to be that HWINEVENTHOOK is defined twice in
windef.h
#if(WINVER >= 0x0400)
DECLARE_HANDLE(HWINEVENTHOOK);
#endif /* WINVER >= 0x0400 */
and then in winable.h it's
#if WINVER < 0x0500 // these structures and functions
// are in NT 5.00 and above winuser.h
typedef DWORD HWINEVENTHOOK;
However, I just looked up WINVER for vista and it is 0x0600 and windows XP is 0x0501 so why is DWORD being defined? I'm at a loss. Anyone help?
According to this MSDN forum thread:
winable.h was moved from the Windows
SDK in July 2005 because functionality
was duplicated in winuser.h. It was
determined at that time that efforts
would be better spent on updating
winuser.h to Windows Vista-level
functionality rather than updating the
functionality of both files.
What version of the Windows SDK are you using, and what Windows version is your code targetting? The target Windows version may be specified in a makefile, project file, or header file. Compiling your code on Vista doesn't necessarily mean that the target version is Vista.
Also, have you tried switching from winable.h to winuser.h?
You might need to explicitly set WINVER to the version corresponding to the minimum version of Windows you are targeting. I suspect its default value is not much above Win2K...
You could check its default value with a quick (untested) hack like this:
#include <windows.h>
#include <stdio.h>
int main(int argc, char **argv) {
printf("WINVER=0x%04x\n", WINVER);
return 0;
}
Compiled as a console app and run at the command prompt it might provide a clue. Otherwise, you'll spend ages chasing through include files trying to identify where it set the default.
Edit: In general, it is safest to always specify WINVER for a project. Either do it in the project settings in Visual Studio (and for all builds, not just the current build!) or do it in a common header file included by every module in the project. Doing so explicitly will reduce the chance that different build environment might have a different assumption.