I would like to create a static library in C++ to store my functions.
I'm aware this question has been asked on the Cplusplus forums but I could really use a
more accurate description of what to do.
As far as I'm aware you create a new Win32 program and then add the header file (.h) and the
code file (.cpp).
So in fact I have a few questions.
1 - How do I put my code into these files?
Do I use the .cpp?
2 - I did manage to make a simple library with an add function alone, but after compiling
and building it I was unable to #include it in a program. Why is this?
Could someone please write out a step-by-step approach to making this so I can finally do it.
I am aware MSDN has a tutorial for this, and I have looked at it.
The thing is it uses a OOP approach to making the static library, and the calls to the
functions within the library use the :: operator (think its an operator), too often which is what I want to avoid.
Would like to start simple, basically.
Thanks for any help given.
The idea of a static library, is that you write your code as usual, but you compile it as a static library. The users of a static library still need your header files, but they don't need your .CPP files anymore, because the actual implementation is contained in your static library file.
To use a library, you include the header files you need, and then link the library file with your program.
Here is a link to the microsoft walkthrough.
http://msdn.microsoft.com/en-us/library/vstudio/ms235627.aspx
How to create and use a static library using Visual Studio
Here is excactly how you do it in Visual Studio 2012.
To create a library, create a new C++ project. In the wizard, at Application Settings, choose Static library. Uncheck Precompiled header.
Create your library as you want. Don't forget to declare everything in header files.
Compile the project as you usually would. This creates a .lib file in the debug folder of your solution
To use the library, create an application as you usually would.
To link the library with your project, drag the .lib file to your project in visual studio.
To let visual studio find your header files, right click your project. Choose Properties->Configuration properties->C/C++. There is a input box called Additional Include Directories. Here, you have to write the path to the header files of you library.
You can now use the header files as if they where made by your project directly. The implementation of your library is taken from the .lib file, and everything should compile and run well.
Another option, is referencing the whole libary project in your application. To do this, you must get the library project in your solution. Right click your solution in Visual Studio->Add->Existing Project. Then you have to reference the project. Right click your project->References->Common Properties->Framework and References->Add New Reference->Choose your project. Now you can edit your library in this solution and use it directly in your application.
Related
My C++ project is dependent on a huge project. My project uses many dll's from huge project. It take about few hours to install the huge project and I want to remove the need to install the huge project for someone else.
After research I understand there is two methods to compile and link using dll 1) Using a lib and header.
2) Using loadlibary method.
In loadlibrary method I need to know exactly the methods needed to load. Since I don't know this I went with option 1. Please correct me if I am wrong.
Currently I have included the path to the big project in the compiler additional dependencies configuration option. I want to share the included header with my team. The big project has lot of headers that is not used by my dependency dlls. I tried copying all the headers but some .cpp are directly used without any headers.
Is there any way I can copy only the header files needed from the huge project? Possibly automatically using less manual work. Currently the headers and cpp are about 1gb which I can't share via github. If I can't copy the headers is there anyway I could automatically generate all the dependency definitions to a file and use it? Please let me know whats the standard way of handling situations like this.
You can dynamically build and link to the library (dll).
To do so, you need to
include the folder containing the .h files with the compiler -I argument -IC:\path\
link to the folder including the dll with the linker -L argument -LC:\path\
The lib has to be compiled with the same compiler & same platform
I have paid for an expensive .dylib file however, the code is non objective-c in short, horrendous! I am thinking of creating a wrapper of some sort like an API to make interfacing with this .dylib nightmare free. How is this done? Here is what I was going to do:
Create a customDylibSDKWrapper .h and .m file, and have the appropriate function names that will keep things simple, and in the .m file, add all the c++ functions inside each objective-c function. So then all I would need to do in the future is, call the objective-c function and that will automatically call the C++ code.
Is this the correct way of creating a wrapper?
If it is, this does not create a private hidden wrapper, all the code will still be visibile. Is there anyway to package the .dylib file along with my objective-c .m files exposing only the objective-c .h file?
If anyone is curious to see the horrendous code feel free to look at this link: link to hard to decipher code
You can create both a dynamic library and a static library with Xcode.
Creating dynamic libraries isn't officially supported, and it requires editing some XML, and apps that include dynamic libraries won't be approved by Apple, so I'm not going to bother with dynamic libraries in this answer.
You can however easily create static libraries.
Step one: start a new project, being sure to select Cocoa Touch Static Library when you create the project:
Step two: Write your code.
Step three: Push the run button. Since your static library should have any code that will actually run, nothing should actually run. Instead, Xcode builds the library.
In the view on the left that shows all your folders and files and such, you should see a .a file, which is the compiled library. You can find on your computer by right-clicking and clicking "Show in Finder".
Now all that's left is distributing the .h/.a files to whoever you want.
when we want to use a static library (*.lib) file we reference it in project properties in additional library dependencies portion, what i do want to know is how exactly VS handle this linkage? in other words is there any alternative way to this VS task -linking a library in link step- by piece of code or anything else?
You can use
#pragma comment(lib, "<library path and name>")
Then you don´t need to add your library into project settings
To figure out what Visual Studio has done, add the reference. Now, using your source control/favorite diff tool, compare the old .vcxproj file to the new one. You should see what changes were made to the .vcxproj, which is the file used to drive the build.
I assume that you are using source control and the .vcxproj is under source control. If not, make a copy of the original .vcxproj somewhere to compare with. (Also, strongly consider using source control. :-] )
In C# it's pretty simple to add a project reference that will build the dependency, put the resulting assembly in the original's Debug/ directory and properly compile against that assembly.
So at the moment, I have a project with the Main() and a static library project in one solution. However, when I compile the Main() project and I look in the bin/Debug/ directory I don't find either the Static.lib file or the .obj files, which I think would need to be there, or something... I'm getting linker errors.
I think maybe I have to Configure the project to find the .obj and the .lib file produced by the static library project (which compiles fine, and actually produces those files.)
I'm missing something, and I'm not very well versed in Visual Studio with C++.
How do I add the reference in the Main project to use the library produced by the static library project?
The first thing you'll have to unterstand is, that static libraries are nothing like .NET assemblies. They are linked into the .exe and are not distributed as separate entity.
Your linker errors are most likely a result of you not linking to the library.
There are several ways to define libraries that have to be linked.
One is int the project settings under linker -> input -> additional dependencies,
the other would be the cheap route via #pragma comment(lib, "path to library")
You can add the name of the .lib files you need by going in project property->Linker->Input->Additional Dependencies
Then you will have to give the folder where your library is in VC++ Directories->Library Directerories.
Here is a very comprehensive answer: visual c++: #include files from other projects in the same solution
It describes the settings for the linker but also other essentials when referencing another C++ project. (especially when coming from C# but not being too versed in C++)
In .NET, one of design goals was due make this process a lot easier and automatic. Mission accomplished there.
In the native C++ world, the process is much more manual. Here is roughly my process for hooking up different modules together.
Include all relevant modules in the solution.
Set the output
directory of each project to the same directory. Either Right click
on each project, choose properties and in general, set the output
directory to: $(SolutionDir)\Bin\$(Configuration)\$(PlatformTarget).
For reduced headaches, Set this for all configurations and platforms.
Then all the files will be placed in somewhere like
\your-solution\bin\Debug\x64.
Set the project dependencies - Right click on each project that will be linking to another -> Choose Build Dependencies and select the referenced projects.
Set up the linking process, by Right clicking on the calling project and choosing
properties. Go to linker -> Input and add: $(SolutionDir)\Bin\$(Configuration)\$(PlatformTarget)\MyLibrary.lib
For the actual functions that are going to linked to, I set the
function declarations to something like (There are a lot of variations on the function declaration, a bit outside of the scope here):
#define DllExport __declspec( dllexport )
extern "C" void DllExport WINAPI` Testing();
In actual cpp file of the calling function, I add something like the following:
#include "..\MyLibrary\mylibrary.h"
Then in the actual calling function. simply add called function:
Testing();
If you are building multiple projects in the same solution, use a project reference to automatically link your libraries and executables together:
https://learn.microsoft.com/en-us/visualstudio/msbuild/common-msbuild-project-items?view=vs-2019#projectreference
which is explained pretty well here:
https://milania.de/blog/Project_references_in_Visual_Studio_and_C%2B%2B
The advantage to this approach, is that the build order will be correct. Using Additional Dependencies, as suggested in the other answers, will not maintain the proper build order.
I am developing a C++ library that I want to pass on to my team. The library has just one class with a bunch of methods.
So, I have developed the class definition file (X.cpp) and a corresponding class declaration file (X.h).
Here are my questions --
In Visual Studio 2005, whats is the most straight forward way to build this library as a DLL, such that I get the following files:
X.lib : which I can pass to my team so they can link against my library
X.dll : which I can pass to my team for run-time
Instead of a DLL, should I rather be going the static library way ?? If so, how do I go about doing this in Visual Studio 2005 & will this give me a X.lib file that I can pass on to my team ?
Any explanations or references are very welcome.
Thank you very much.
The easiest way to build a DLL, is New->Project->Win32 Console Application. Then on the dialog select DLL and select "Exports Symbols". This will synthesize a dll with a .h, and .cpp file which demonstrate how to export your classes. You can get rid of this .h/.cpp but first import your class add the appropriate #ifndef statements. Now as far as DLL versus Static library if its a single small class, that doesn't change particularly often you might be better off with a static library, its simple, its concise, it doesn't add another dependency which needs to be shipped with your product. A DLL is nice if the code in the .cpp file changes often (ie. the function implementations) because you can just swap in the new DLL.
From your description, it looks like you already have a Visual C++ project (correct me if I'm wrong). If so, when you go into project properties, under "General" you can find "Configuration Type" - switch it to "Static library" or "Dynamic library" as needed.
If you choose "Static library", then you will just get a .lib file that can be immediately used.
If you choose "Dynamic library", and you export any functions from your DLL (e.g. by marking them with __declspec(dllexport)), an export .lib will be generated automatically.
It's hard to tell which option is preferable without knowing the specifics of what you're doing. In general, I'd recommend defaulting to static libraries, because it's usually good enough, and there are more traps when dealing with DLLs (especially ones that export C++ symbols).
I think that, in most cases, a dll is a better choice than a static lib because your team will not have to recompile their code when you distribute a new version of your library.
I struggle with this too sometimes.. because I can't find where the elusive setting is within C++ Project Properties.. So I decided to jot it down for my own sanity as a blog post.
HTH