Guys I was trying in VS to do something like:
#ifdef _MSC_VER
#include "stdafx.h"
#endif
but I'm getting an error telling me:
C1020: unexpected #endif
What is the correct way to do it?
Edit
/This is content of stdafx.h/
// stdafx.h : include file for standard system include files,
// or project specific include files that are used frequently, but
// are changed infrequently
//
#pragma once
#include "targetver.h"
//#include <stdio.h>
//#include <tchar.h>
#include <iostream>
using std::cout;
using std::cerr;
// TODO: reference additional headers your program requires here
You cannot put conditionals around stdafx.h because of the way MSVC precompiled headers work. It basically replaces everything once stdafx.h has been found (and usually requires #include "stdafx.h" to be the first line in the file) with the precompiled header contents, so it is as if you never wrote #if _MSC_VER and have an extra #endif.
Two solutions:
1) Do not use precompiled headers in your project. You can still use stdafx.h to include all the headers you require but compilation will be slow.
2) Put the conditional compile within the stdafx.h file.
(Taken from here)
Related
I have the problem with precompiled header. It looks somewhat like that
ftpch.h
#pragma once
#include <vector>
#include <iostream>
#include <string>
#include <Windows.h>
ftpch.cpp
#include "ftpch.h"
Then I have a header file and cpp in my dll library.
test.h
#pragma once
// DLL_EXPORT is a macro that changes for dll and console app like that:
// __declspec(dllexport) and __declspec(dllimport)
class DLL_EXPORT Test
{
std::string foo() {return "ara ara"};
}
And this code compiles fine when I compile my dynamic library project, but fails to compile when I include "test.h" in my console app project and try to compile it. The error I get is:
C2039: 'string' is not a member of 'std'
Your header files should always be self-sufficient. Include your libraries (in this case <string>) where you need them, everywhere you need them, and only where you need them.
If your header requires a certain library to function, include it in that file; don't reply on a different header to have included that library already, because if that different file changes, you're out of luck.
You've already got #include guards through #pragma once, so adding #include <string.h> to the header files that need it won't cause collision, and will also make them more maintainable and easy to interpret.
For some reason I can't explain, the compiler is outputting an error saying that it found an unexpected #else token.
This occurs at the beginning of the file :
#if defined( _USING_MFC )
#include "stdafx.h"
#else
#include <windows.h>
#endif
There is nothing before that peice of code expect several (single-line) comments.
This error occurs in a .cpp file. What you see above is the beginning of the file. There is nothing before that.
I tried adding the following code before the code defined above, and the error is now an unexpected #endif
#if 1
#include "stdafx.h"
#endif
So I suspect there is an issue with the included stdafx.h file which contains the following code :
#ifndef STDAFX_H_INCLUDED
#define STDAFX_H_INCLUDED
#include <Afx.h>
#include <Windows.h>
using namespace ATL;
#endif // STDAFX_H_INCLUDED
There's really nothing special about it. I'm also including this stdafx.h file from a stdafx.cpp file that only contains the #include statement, and it compiles correctly.
Here are the project preprocessor definitions :
_DEBUG
_WIN32_WCE=$(CEVER)
UNDER_CE
WINCE
DEBUG
_WINDOWS
$(ARCHFAM)
$(_ARCHFAM_)
_UNICODE
UNICODE
_TERMINAL_FALCONX3_CE6
_NO_CPP_EXCEPTIONS
_DONT_INCLUDE_WS_HEADERS
_USING_MFC
And some extra informations :
Compiling for Windows CE 6 using Visual Studio 2008.
What would be causing this ? Thank you.
Based on the name stdafx, I assume it is a precompiled header.
A precompiler header must be the first include (preprocessor) directive in the file, you can't put anything (not even an ifdef) before it. The only exception being a few comment lines, as those would be ignore anyway.
Based on your example, you should put the #ifdef _USING_MFC into your stdafx.h, and include Afx.h there.
I'm using rapidjson, which is an all header library. In rapidjson.h, there is a macro RAPIDJSON_ASSERT, in one of my cpp files, I would like to redefine it, so I have this code at the top of my file:
#include "stdafx.h" // for windows
#pragma push_macro("RAPIDJSON_ASSERT")
#define RAPIDJSON_ASSERT(x) if(!(x)) throw std::logic_error("rapidjson exception");
#include "rapidjson/rapidjson.h"
#include "rapidjson/document.h"
#include "rapidjson/stringbuffer.h"
#include "rapidjson/writer.h"
....
....
#pragma pop_macro("RAPIDJSON_ASSERT")
Here is the whay that rapidjson.h defines RAPIDJSON_ASSERT:
#ifndef RAPIDJSON_ASSERT
#include <cassert>
#define RAPIDJSON_ASSERT(x) assert(x)
#endif // RAPIDJSON_ASSERT
The documentation states that to override the RAPIDJSON_ASSERT logic, you just have to define RAPIDJSON_ASSERT before you include any of the files.
The issue is that when I run the code in the debugger, RAPIDJSON_ASSERT is not being redefined. I checked stdafx.h for anything which would include the rapidjson header files, and there isn't anything.
I was under the assumption that each compilation unit should run through the header files.
Note that if I move the redefinition of the macro into stdafx.h I get the macro redefined, but I was hoping to be able to do it per compilation unit.
It seems like you want to change the definition of RAPIDJSON_ASSERT for the rapidjson code itself
If so, you need to add a #define after the place where it is defined. Unless you want to edit the rapidjson.h file, the only alternative is to do this:
#include "stdafx.h" // for windows
// One would assume that the macro gets defined somewhere inside here
#include "rapidjson/rapidjson.h"
// Compiler will complain about macro redefinition without this #undef
#undef RAPIDJSON_ASSERT
#define RAPIDJSON_ASSERT(x) if(!(x)) throw std::logic_error("rapidjson exception");
#include "rapidjson/document.h"
#include "rapidjson/stringbuffer.h"
#include "rapidjson/writer.h"
Now the definition of RAPIDJSON_ASSERT is changed for the rest of the header files. You don't need the push_macro and pop_macro shenanigans - macros only are valid for each unit
Note that it's not a a good thing to redefine things for libraries using #define
Motivation:
I want to enable the memory detection of VC++, which requires that some statements must be at the forefront as follows:
#define _CRTDBG_MAP_ALLOC
#include <stdlib.h>
#include <crtdbg.h>
Question:
Suppose I have a header file forefront.h, what I want is the following effect:
a.cpp
#include <any_other_one.h>
#include <forefront.h> // An compiler error generated here!
b.cpp
#include <forefront.h> // OK
#include <any_other_one.h>
How to implement?
Create your own header file with the following contents:
#define _CRTDBG_MAP_ALLOC
#include <stdlib.h>
#include <crtdbg.h>
Now use the Forced Includes setting in the Advanced section of the project's settings. Any file specified there will be included before all others, in the order specified.
Since what you're really asking is how to ensure _CRTDBG_MAP_ALLOC is defined in all compilation units, use the VC++ project system to add that definition. Go to the project properties dialog, and in the C++ Preprocessor section add _CRTDBG_MAP_ALLOC to the Preprocessor Definitions line.
I think this is the most non-intrusive solution I come up with,
put the following at the beginning of forefront.h,
#if (__LINE__ != 0)
#error ERROR_FORE_FRONT_IS_NOT_THE_FIRST_TO_INCLUDE
#endif
you don't need to change others.h.
I tested this code with GCC 4.6.3.
I guess something like this might work:
other.h
#ifndef OTHER_H_
#define OTHER_H_
...
#endif
forefront.h
#ifdef OTHER_H_
#error Wrong include order
#endif
I've tried placing the following in my C++ code:
#ifdef _WIN32
#include "stdafx.h"
#endif
but I getan error:
PCH warning: header stop cannot be in a macro of #if block. An IntelliSense PCH file was not generated.
I'm trying to let my code work both on windows and linux, stdafx.h does not work on linux where it's a must on visual studio.
Is there another way to use the include with ifdef?
Unfortunately you can not do that with precompiled header and using Microsoft MSVC. The MSVC totally ignores all code (and whatever garbage) lines that precede that #include "stdafx.h" line. As result the #endif will be unexpected to it.
Put that #ifdef _WIN32 and what not inside of stdafx.h.
I have just created an empty stdafx.h. With follow content for solutions without pre-compiled headers
#pragma once
//this is only for using Common modules with Precompiled headers. We can't disable it using a preprocessor(
//https://stackoverflow.com/a/36271896/6160632