I have two projects in my C++ MSVC solution:
A static library project
A .exe project that has a reference to the Project #1 (the static library project)
Project #1 has additional include directories, C:/addincdir .
Project #1's header file, p1header.h includes the header hd.h from C:/addincdir.
Project #2 includes p1header.h .
But when I build the solution, I get an error: Project #2 cannot open include file hd.h (cannot find/locate the header file.) I know the solution is to add C:/addincdir to Project #2's additional include directories.
But is there a way for MSVC to automatically add referenced project's additional include directories? Or is there some kind of macro like $(Project1additionalincludedirectories) that includes Project #1's additional include directories and I can add this variable to Project #2's additional include directories?
It just wouldn't be practical to copy-paste every additional include directory from Project #1 to Project #2.
No. There is no way to automatically add the folders.
(step 5 in Walkthrough: Create and use a static library - Use the functionality from the static library in the app)
To include a header file (listed in the additional include folders) you need to use <... >
#include <header.h++>
You can use an environmental variable such as using MORE_INC_DIR and set it to C:/addincdir1;C:/addincdir2;C:/addincdir3; and put $(MORE_INC_DIR) in the additional include directories of both projects.
Related
I'm working on an existing Visual Studio 12 "Solution" from another team..
In one of its "project"s,, there's a header file that includes a file from another static library projecet..
So Lets say the solution structure looks something like this:
Project A (Static Library Project)
\__ someFile.h
Project B (Static Library Project)
\__ someLibrary.h
In someFile.h,
...
#include "someLibrary.h"
...
and this loads the library successfully.. BUT this is strange because the path to someLibrary.h is NOT SPECIFIED anywhere in Project A's settings!!
I've checked Configuration Properties => VC++ Directories => Include Directories but path to someLibrary.h is NOT specified here..
Since Project A is a static library with NO cpp files (has only header files), It does not have a Configuration Properties => C++ => Additional Include Directory Option at all... (It only has the Librarian option)
And of course someLibrary.h is not in the same directory as someFile.h.
Finally, in Project A's Common Properties, Project B is not referenced either...
So my question is : How the hell does someFile.h know where someLibrary.h is?
How is it including it??
Is there any other places in project settings/etc where additional include directory can be specified..?
UPDATE:
when I right click on the #include statement and click "Open Document 'someLibrary.h'",
I do see a following VS error box:
File 'someLibrary.h' not found in current source file's directory or in build system paths.
Nevertheless,, there is NO build error, and Project A uses someLibrary.h with no problem!!
I have recently gone from Code::Blocks to Visual Studio, and in Code::Blocks one could just add a class and then include it straight away. However, whenever I do the same in Visual Studio with the following statement:
#include "includedFile.h"
or
#include "include/includedFile.h"
It doesn't work and instead I get the error:
cannot open include file: 'includedFile.h'; no such file or directory.
Is there some box or setting that I have to tick? Or do I have to add each header as a dependency manually?
Here is the code for the class in question:
Public.h:
#pragma once
class Public
{
public:
static const int SCREEN_WIDTH=1000;
static const int SCREEN_HEIGHT=1250;
Public(void);
~Public(void);
};
Public.cpp:
#include "Public.h"
Public::Public(void)
{
}
Public::~Public(void)
{
}
How it is being included:
#include "Public.h"
I had this same issue going from e.g gcc to visual studio for C programming. Make sure your include file is actually in the directory -- not just shown in the VS project tree. For me in other languages copying into a folder in the project tree would indeed move the file in. With Visual Studio 2010, pasting into "Header Files" was NOT putting the .h file there.
Please check your actual directory for the presence of the include file. Putting it into the "header files" folder in project/solution explorer was not enough.
Go to your Project properties (Project -> Properties -> Configuration Properties -> C/C++ -> General) and in the field Additional Include Directories add the path to your .h file.
And be sure that your Configuration and Platform are the active ones. Example: Configuration: Active(Debug) Platform: Active(Win32).
You need to set the path for the preprocessor to search for these include files, if they are not in the project folder.
You can set the path in VC++ Directories, or in Additional Include Directories. Both are found in project settings.
By default, Visual Studio searches for headers in the folder where your project is ($ProjectDir) and in the default standard libraries directories. If you need to include something that is not placed in your project directory, you need to add the path to the folder to include:
Go to your Project properties (Project -> Properties -> Configuration Properties -> C/C++ -> General) and in the field Additional Include Directories add the path to your .h file.
You can, also, as suggested by Chris Olen, add the path to VC++ Directories field.
I found this post because I was having the same error in Microsoft Visual C++. (Though it seems it's cause was a little different, than the above posted question.)
I had placed the file, I was trying to include, in the same directory, but it still could not be found.
My include looked like this: #include <ftdi.h>
But When I changed it to this: #include "ftdi.h" then it found it.
If your problem is still there it's certainly because you are trying to compile a different version from your current settings.
For example if you set your Additional Include Directories in Debug x64, be sure that you are compiling with the same configuration.
Check this: Build > Configuration Manager... > There is problably something like this in your active solution configuration: Debug x86 (Win32) platform.
For me, it helped to link the projects current directory as such:
In the properties -> C++ -> General window, instead of linking the path to the file in "additional include directories". Put "." and uncheck "inheret from parent or project defaults".
Hope this helps.
I tried the other answers here as well, but my problem had nothing to do with the include paths or files missing incorrect #includes. I had two configurations, each set to the exact same include directories. One configuration could resolve the includes, the other could not.
After selecting my project and going to Project -> Properties, I selected both configurations through the Configuration dropdown -> Multiple Configurations... option. Comparing the two I found that C/C++ -> Language -> Conformance Mode was different. The "incorrect" configuration had a value of Default for some reason, and switching it to Yes or No allowed the paths to be resolved.
TL;DR: If you have one configuration with the same include directories but the other isn't finding the files, I suggest to try comparing the configurations.
If you've tried the other answers and your include file still can't be found, here are some additional debugging steps and sanity-checks:
Ensure that you are building to a platform that is supported by your code. (If not, consider removing this platform as a target)
Verify that the filename/path is correct. Modify your source code to #include the whole absolute path of the header file instead, and see if the file can be found now. If not, copy-paste the path from your source code into a command line to validate that the file exists at that full path with no typos. Open the header file to ensure you have read access. (Change the source code back when done.)
If you've already added the path to Additional Include Directories, try clicking the drop-down combo box for Additional Include Directories, and select <Edit...>. This will show you evaluated values of paths. (If it does not show the correct evaluated values, variables in your path might not be set. Click Macros>> to see variables.) Copy-paste the evaluated path into windows explorer to validate that the path exists.
Create a new empty C++ "Windows Console Application" project. Set just the one Include Directory, and #include just the one file in your main.cpp, and see if that builds.
I have a Visual Studio solution containing 2 project: main project and test (via googletest). In main project I have myclass.cpp and myclass.h files. When I'm trying to compile test project, there are bunch of LNK2019 errors when I include "myclass.h" in my test.cpp file, but everything works fine if I include "myclass.cpp" instead. Is that normal? As far as I know, including of .cpp files is not recommended and generally can be avoided. Any suggestions?
It's normal. If you have 2 projects, 2 binaries will be generated.
Don't include the cpp file.
Instead, link the binaries together.
main project - generates .lib file and either .dll or .exe.
test project - includes header from main. You need to add the .lib generated by main in the additional dependencies of the test project. Somewhere in the Project Settings - Linker Options - Additional Dependencies.
You can generate both .exe and .lib file from a single project. To do this you set:
exe in Linker -> General -> Output File
lib in Linker -> Advanced -> Import Library
You may also need to mark exported functions with __declspec( dllexport ) in the .exe project (see docs), otherwise compiler won't generate a .lib file.
Steps to Use Classes form another project (Add header and solver linker errors)
1) To be able to add the header from another project, first go to "Properties > c++ > General > Additional Include Directories" and add the directory that contains the header. Now you will be able to add the header of the class from the other project, but running the project will still cause Linker Errors.
2) Add __declspec(dllexport) before the class you are using for the other project. This can be added in the header file of that class. This should be added right before the function or variable or class name. Now you will get a lib file. (if placed in wrong place, you can get this warning: https://msdn.microsoft.com/en-us/library/eehkcz60.aspx)
3) "Properties > Linker > Additional Library Directories". Specify the location of the lib file that is generated.
4) "Properties > Linker > Input > Additional Dependencies”: Add the name of the lib file.
I am currently trying to compile a simple program that includes two header files. I see them in the Solution Explorer, where I included them through "include existing files". However, when I run my program it get the following error.
fatal error C1083: Cannot open include file: 'FileWrite.h': No such file or directory. THe problem is that I see the file included in the Header's folder and in the code I have written:
#include "FileWrite.h"
and then the rest of the program code.
Is there something else needed to do so that the compiler can see the header file and link it to the .cpp file I'm trying to compile?
If you write in your code something like #include "FileWrite.h" you need to make sure compiler can find that file. There are three options:
FileWrite.h should either be in the same directory as your source code file (.cpp) or
Path to that header file should should be listed in project's Properties (in C/C++ -> General -> Additional Include Directories) or
Path could be set in your VisualStudio - add it to Include Files in Tools->Options->Projects and Solutions->VC++ Directories
Which of these options shell be used depends on whether that header originates from this project (1st option) or some other project (any of other two options).
There are two ways to do this.
1) Only for the current project
Select your project -> properties -> C/C++ -> General -> Additional Include Directories -
Include your header file directory.
2) For all projects
Tools -> Options -> VC++ Directories -> Include files - Add the header file directory.
Refrain from using 2, as it would be difficult to figure out dependencies for a project when compiling it on a system different than yours.
When including files the compiler first looks in the current directory (the directory which contains the source .cpp file) then it looks in the additional include directories. If FileWrite.h isn't in the same directory as your source file check the additional included directories.
In the project's property page look at the additional include directories and see if they include the folder in which FileWrite.h is in.
You said the file is in the "headers" folder. This could either mean the headers filter or an actual headers directory on the filesystem. When including a file from your own project you need to specify the path from the file you're including into. So, if you had something like so:
src/main.cpp
include/my_object.h
You would use #include "../include/my_object.h" in main.cpp.
That's for directories. The folders you see in your project are called filters and have absolutely no relation to the directory structure of your project unless you force it to. You need to be paying attention to what the structure looks like in windows explorer to ascertain what path to use in an include statement.
I am working on a game using Visual C++. I have some components in separate projects, and have set the project dependencies. How do I #include a header file from a different project? I have no idea how to use classes from one project in another.
Settings for compiler
In the project where you want to #include the header file from another project, you will need to add the path of the header file into the Additional Include Directories section in the project configuration.
To access the project configuration:
Right-click on the project, and select Properties.
Select Configuration Properties->C/C++->General.
Set the path under Additional Include Directories.
How to include
To include the header file, simply write the following in your code:
#include "filename.h"
Note that you don't need to specify the path here, because you include the directory in the Additional Include Directories already, so Visual Studio will know where to look for it.
If you don't want to add every header file location in the project settings, you could just include a directory up to a point, and then #include relative to that point:
// In project settings
Additional Include Directories ..\..\libroot
// In code
#include "lib1/lib1.h" // path is relative to libroot
#include "lib2/lib2.h" // path is relative to libroot
Setting for linker
If using static libraries (i.e. .lib file), you will also need to add the library to the linker input, so that at linkage time the symbols can be linked against (otherwise you'll get an unresolved symbol):
Right-click on the project, and select Properties.
Select Configuration Properties->Linker->Input
Enter the library under Additional Dependencies.
Since both projects are under the same solution, there's a simpler way for the include files and linker as described in https://learn.microsoft.com/en-us/cpp/build/adding-references-in-visual-cpp-projects?view=vs-2019 :
The include can be written in a relative path (E.g. #include "../libProject/libHeader.h").
For the linker, right click on "References", Click on Add Reference, and choose the other project.
Expanding on #Benav's answer, my preferred approach is to:
Add the solution directory to your include paths:
right click on your project in the Solution Explorer
select Properties
select All Configurations and All Platforms from the drop-downs
select C/C++ > General
add $(SolutionDir) to the Additional Include Directories
Add references to each project you want to use:
right click on your project's References in the Solution Explorer
select Add Reference...
select the project(s) you want to refer to
Now you can include headers from your referenced projects like so:
#include "OtherProject/Header.h"
Notes:
This assumes that your solution file is stored one folder up from each of your projects, which is the default organization when creating projects with Visual Studio.
You could now include any file from a path relative to the solution folder, which may not be desirable but for the simplicity of the approach I'm ok with this.
Step 2 isn't necessary for #includes, but it sets the correct build dependencies, which you probably want.
#include has nothing to do with projects - it just tells the preprocessor "put the contents of the header file here". If you give it a path that points to the correct location (can be a relative path, like ../your_file.h) it will be included correctly.
You will, however, have to learn about libraries (static/dynamic libraries) in order to make such projects link properly - but that's another question.
You need to set the path to the headers in the project properties so the compiler looks there when trying to find the header file(s). I can't remember the exact location, but look though the Project properties and you should see it.
Try to avoid complete path references in the #include directive, whether they are absolute or relative. Instead, add the location of the other project's include folder in your project settings. Use only subfolders in path references when necessary. That way, it is easier to move things around without having to update your code.