I have two projects; a static library and an executable (standard Win32 setup, using the multithreaded debug dll setting for both).
In my libray, I have a Globals.h, with the following code:
#ifndef _GLOBALS_H
#define _GLOBALS_H
#include <SDL.h>
#include <string>
namespace Eng
{
bool Run = true;
SDL_Window *Window = NULL;
SDL_GLContext GlContext;
Uint32 WindowFlags = SDL_WINDOW_OPENGL;
}
#endif
This is all fine and dandy, and within that project everything works fine. However, as soon as I include that file within more than one file in my executable project (all protected by inclusion guards), I start getting multiply defined symbol errors for each variable within Globals.h.
As well, I'm getting quite a few macro redefinition warnings from math.h (M_PI macro redefinition). I'm not sure if this is linked, but it seems likely due to the similar nature of error (guards defined in one project seemingly not applying in the other).
Anyone have any ideas how to resolve this? I feel like I'm missing some vitally important compiler setting somewhere :(
Error: cannot open source file "GL/glew.h"
I have the following code :
//Include GLEW
#include <GL/glew.h>
//Include GLFW
#include <GLFW/glfw3.h>
//Include the standard C++ headers
#include <stdio.h>
#include <stdlib.h>
//Define an error callback
static void error_callback(int error, const char* description)
{
...
I took from there: http://www.41post.com/5178/programming/opengl-configuring-glfw-and-glew-in-visual-cplusplus-express#part4
In order to have a somewhat portable solution, before I even started Visual Studio 2013 I created two System Environment Variable in windows.
GLEW=C:\Install\Development\C++\Framework\glew-1.10.0-win32\glew-1.10.0
GLFW=C:\Install\Development\C++\Framework\glfw-3.0.4.bin.WIN32\glfw-3.0.4.bin.WIN32
So in my project I could for instance write a additional include folder as: %GLEW%\include
As I said, it builds fine and runs fine as well.
Yet, not having intellisense behave properly is really annoying.
How to fix it?
My syntax was actually wrong, you cant use global environment variable in VS using %<name>% but you have to use $(%<name>).
Wherever I wrote %GLEW%\include I should have $(GLEW)\include.
It's working fine now.
Though I'm completely clueless why it built.
This post: https://stackoverflow.com/a/11543754/910813 got me to remind that.
I am new to C++. I just started! I tried a code on Visual C++ 2010 Express version, but I got the following code error message.
------ Build started: Project: abc, Configuration: Debug Win32 ------
ugo.cpp
c:\users\castle\documents\visual studio 2010\projects\abc\abc\ugo.cpp(3): fatal error C1083: Cannot open include file: 'iostream': No such file or directory
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========
This is the code:
// first.cpp -- displays a message
#include <iostream> // A PREPROCESSOR directive
int main(void) // Function header
{ // Start of a function body
using namespace std;
cout << "Come up and C++ me sometime.\n"; // Message
// Start a new line
cout << "Here is the total: 1000.00\n";
cout << "Here we go!\n";
return 0;
}
Replace
#include <iostream.h>
with
using namespace std;
#include <iostream>
Some things that you should check:
Check the include folder in your version of Visual Studio (in "C:\Program Files\Microsoft Visual Studio xx.x\VC\include", check for the file which you are including, iostream, make sure it's there).
Check your projects Include Directories in <Project Name> → Properties → Configuration Properties → VC++ Directories → Include Directories (it should look like this: $(VCInstallDir)include;$(VCInstallDir)atlmfc\include;$(WindowsSdkDir)include;$(FrameworkSDKDir)\include;)
Make sure that you selected the correct project for this code
(menu File → New → Project → Visual C++ → Win32 Console Application)
Make sure that you don't have <iostream.h> anywhere in your code files, Visual Studio doesn't support that (in the same project, check your other code files, .cpp and .h files for <iostream.h> and remove it).
Make sure that you don't have more than one main() function in your project code files (*in the same project, check your other code files, .cpp and .h files for the* main()` function and remove it or replace it with another name).
Some things you could try building with:
Exclude using namespace std; from your main() function and put it after the include directive.
Use std::cout without using namespace std;.
I had this exact same problem in Visual Studio 2015. It looks like as of Visual Studio 2010 and later you need to include #include "stdafx.h" in all your projects.
#include "stdafx.h"
#include <iostream>
using namespace std;
The above worked for me. The below did not:
#include <iostream>
using namespace std;
This also failed:
#include <iostream>
using namespace std;
#include "stdafx.h"
You are more than likely missing $(IncludePath) within Properties → VC++ Directories → Include Directories.
Adding this should make iostream and others visible again. You probably deleted it by mistake while setting up your program.
If your include directories are referenced correctly in the VC++ project property sheet → Configuration Properties → VC++ directories → Include directories, the path is referenced in the macro $(VC_IncludePath).
In my Visual Studio 2015 this evaluates to:
"C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\include"
using namespace std;
#include <iostream>
That did it for me.
It is possible that your compiler and the resources installed around it were somehow incomplete. I recommend re-installing your compiler: it should work after that.
I got this error when I created an 'Empty' console application in Visual Studio 2015. I recreated the application, leaving the 'Empty' box unchecked. It added all of the necessary libraries.
Make sure you have Desktop Development with C++ installed.
I was experiencing the same problem, because I only had Universal Windows Platform Development installed.
Microsoft Visual Studio is funny. When you're using the installer, you must checkbox a lot of options to bypass the .NET framework (somewhat) to make more C++ instead of C# applications, such as the CLR options under desktop development... in the Visual Studio installer.... the difference is the C++ Win32 console project or a C++ CLR console project.
So what’s the difference? Well, I'm not going to list all of the files CLR includes, but since most good C++ kernels are in Linux... So CLR allows you to bypass a lot of the Windows .NET framework because Visual Studio was really meant for you to make applications in C#.
Here’s a C++ Win32 console project!
#include "stdafx.h"
#include <iostream>
using namespace std;
int main()
{
cout << "Hello, World!" << endl;
return 0;
}
Now here’s a C++ CLR console project!
#include "stdafx.h"
using namespace System;
int main(array<System::String ^> ^args)
{
Console::WriteLine("Hello, World!");
return 0;
}
Both programs do the same thing .... the CLR just looks more frameworked class overloading methodology, so Microsoft can great its own vast library you should familiarize yourself with if so inclined.
Keywords (C++)
Other things you'll learn from debugging to add for error avoidance:
#ifdef _MRC_VER
#define _CRT_SECURE_NO_WARNINGS
#endif
If you created an environment variable with the name IncludePath, try renaming it to something else.
This name will override $(IncludePath) inside project properties.
Quick fix for small programs:
Add: #include <cstdlib>
In my case, my Visual Studio 2015 installed without selecting C++ package, and Visual Studio 2017 is installed with the C++ package. If I use Visual Studio 2015, opening a C++ project will show this error, and using Visual Studio 2017 will be no error.
I had this problem too. I used this code (before main();) in Visual Studio 2022, and it turned OK:
#include "pch.h"
#include <iostream>
using namespace std;
using namespace winrt;
using namespace Windows::Foundation;
In my case, the error occurred when I created a file in VS Code, without giving the .cpp extension. It resolved when I renamed it with the .cpp.
// first.cpp -- displays a message
#include <iostream> // a PREPROCESSOR directive
using namesapce std;
int main() // function header
{ // start of a function body
///using namespace std;
cout << "Come up and C++ me sometime.\n"; // message
// start a new line
cout << "Here is the total: 1000.00\n";
cout << "Here we go!\n";
return 0;
}
This is the first question I have found myself not being able to get to the bottom of using my normal googling/stack overflowing/youtubing routine.
I am trying to compile a minimal Lua program inside of a C++ environment just to ensure my environment is ready to development. The Lua language will be later used for User Interface programming for my C++ game.
First some basic information on my environment:
Windows 7 64-bit
Visual studio 2010
Lua for Windows 5.1 (latest build I could download from google code)
Here is the code I am trying to compile:
// UserInt.cpp : Defines the entry point for the console application.
//
#pragma comment(lib,"lua5.1.dll")
#include "stdafx.h"
#ifndef __LUA_INC_H__
#define __LUA_INC_H__
extern "C"
{
#include "lua.h"
#include "lauxlib.h"
#include "lualib.h"
}
int _tmain(int argc, _TCHAR* argv[])
{
lua_State * ls = luaL_newstate();
return 0;
}
#endif // __LUA_INC_H__
Here is the Error I am getting:
1>UserInt.obj : error LNK2019: unresolved external symbol _luaL_newstate referenced in function _wmain
1>c:\users\deank\documents\visual studio 2010\Projects\UserInt\Debug\UserInt.exe : fatal error LNK1120: 1 unresolved externals
Things I have tried:
I have read about lua_open()(and several other functions) no longer being used so I tried the newstate function instead. I get the same error. This was more of a sanity check than anything. I am using 5.1 and not 5.2 so I do not think this really matters.
I have also read this thread Cannot link a minimal Lua program but it does not seem to help me because I am not running the same environment as that OP. I am on a simple windows 7 and visual studio environment.
The top pragma comment line was something I saw in yet another thread. I get the same error with or without it.
I have gone into my visual studio C++ directories area and added the lua include to the includes and the lua lib to the libraries.
So it seems like my program is seeing the .h and seeing the symbol. But for some reason it is not getting the .cpp implementation for the functions. This is why I was hoping including that .dll directly would help fix the problem, but it hasn't.
So, I feel like I have exhausted all of my options solving this on my own. I hope someone is able to help me move forward here. Lua looks like an awesome language to script in and I would like to get my environment squared away for development.
I hope it is just some silly error on my part. I believe I have provided as much information as I can. If you need more specifics I will update with info if I can provide it.
Edit1
Tried the solution in this Can't build lua a project with lua in VS2010, library issue suspected
That did not work either.
You'll need to have the library (.LIB) file and add that to VS. Use Project > Properties and go to Linker > Input and add the full .lib filename to the "Additional Dependencies" line. Note that the .LIB is different from the .DLL.
Personally, I prefer adding the source code to my project, over referencing the dynamic link library. The following procedure will let you do as such.
Download the source code ( http://www.lua.org/ftp/ ), uncompress it.
In Visual Studio, choose File > New > Project and choose Visual C++, Win32, "Win32 Console Application".
In your project in Visual Studio, add all the source code, except luac.c. Also delete the main() function out of the file that VS created for you. This is usually given the name of the project you specified with the .cpp file extension. You could just remove this file all-together from the project.
Build and Run.
This is the Lua console
I'm trying to use C++ code in my ios app (I really don't like objective C, I'm going to use it only when necessary [view control, etc]) and while everything seems to be working I get an error in the following test file.
#ifndef prueba3_GlobalStatic_h
#define prueba3_GlobalStatic_h
#include <string>
using namespace std;
class GlobalStatic
{
public:
GlobalStatic();
~GlobalStatic();
string foo();
private:
int integerValue;
};
#endif
When I try to build the project the IDE gives me the following error:
" 'string' file not found"
I've looked around but cannot find a conclusive answer; any help would be appreciated. In essence, how do I get the standard library working?
One cause of missing c++ headers is including them from an objective-c context as opposed to from objective-c++ -- and you can't use the c++ stl from c! The easier solution is to simply change all your .m files to .mm, .mm will send them to the objective-c++ compiler.