I am trying to compile my code on Linux and created a simple make file.
In one of my headers, there is a compile-time conditional #include for a file that emulates Unix's dirent.h.
I put this include in a #if defined(_WIN32) || defined(_WIN64), and yet g++ happily includes the file, which results in endless errors.
The whole block looks like this:
#if defined(_WIN32) || defined(_WIN64)
#include "dirent.h"
#define strncasecmp _strnicmp
#else
#include <unistd.h>
#include <dirent.h>
#include <fcntl.h>
#include <sys/types.h>
#include <utime.h>
#endif
Is there any obvious reason for this to happen?
So, given the comments: Don't call your "compatibility header" "dirent.h" but something like "dirent_compat.h" or "dirent_win.h".
Alternatively, don't add current directory to the include path for system includes (you really shouldn't have <...> includes in current directory anyway)
Related
I'm have variable 'filename' with contents 'code.h', i'm need do this,
#include <filename>
why it's not working? Or #include not works with variables?
#include is for other header files not variables. If you want to conditionally include header files you can use precompiler commands:
//config.h
#define USE_HEADER_CODE_H
//other.h
#include <config.h>
#if defined(USE_HEADER_CODE_H)
#include <code.h>
#else
#include <other_code.h>
#endif
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
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)
How do you implement GLEE in your code so that it loads extensions used within included files?
For example, I have a windows build environment using cygwin and GCC, and am linking to the libraries for GLEE, GLUT, and opengl32.
The includes in my main file are ..
#include <windows.h>
#include <stdio.h>
#include <GL/GLee.h>
#include <GL/glut.h>
#include "SampleUtils.h"
#include "LineShaders.h"
SampleUtils.h declares methods that utilize OpenGL extensions, such as glCreateShader, which are implemented in SampleUtils.cpp. But when I attempt to build these files, the extensions are undeclared. I've tried a couple of different approaches.
Such as including in SampleUtils
#include <GL/gl.h>
#include <GL/glext.h>
which results in undeclared errors
#include <GL/GLee.h>
which throws a long list of errors that seem to relate to the fact that GLEE has already been included.
I can load the same extensions by implementing these methods in the main file, but can't get them to load from an included file. How is this dealt with?
Look in GLee.h:55
#ifdef WIN32
#define WIN32_LEAN_AND_MEAN
#include <windows.h>
#include <GL/gl.h>
#elif defined(__APPLE__) || defined(__APPLE_CC__)
#define GL_GLEXT_LEGACY
#include <OpenGL/gl.h>
#else // GLX
#define __glext_h_ /* prevent glext.h from being included */
#define __glxext_h_ /* prevent glxext.h from being included */
#define GLX_GLXEXT_PROTOTYPES
#include <GL/gl.h>
#include <GL/glx.h>
#endif
Wherever you #include "GLee.h" you don't have to #include gl.h, glext.h, or windows.h.