I am trying to make my own libraries that I can use in future projects. My issue is that the tutorials I find and understand all tell me to create my new project in the solution that my library resides in. This is what I find weird.
My knowledge tells me that a library is supposed to house reusable code and will be used with different projects. Having to force my project to the same solution as my library to use it seems odd and how would it then work if I had to use two different libraries that I have made? I feel like I have missed something obvious.
After searching I have stumbled across something called external libraries, but the only useful thing I understood from this is that "this might be the key".
My question is: How can I create multiple libraries that I can use one or more of in different projects? Or have I misunderstood something crucial and what I am looking for is entirely different? If so, how and where should I create one or more files with reusable code meant to be used across different projects?
This might seem like a no-brainer type of question and I agree! But my googling skills are not up to par to find a solution. Thank you and sorry for using your time.
I am using Visual Studio 2012.
Example of tutorial: https://msdn.microsoft.com/en-us/library/ms235627.aspx
On a C++ Win32 Console App project there is an option on the new project wizard to create a library.
Create your libraries in a single solution and add a post build step to copy them to a "central folder".
In you code that uses the libraries add an include path to your "Central folder"
Add a reference to the library in the project properties, like you would if you were including a windows or boost library.
Related
I'm a unix backend dev that has a small roll in maintaining a visual studio project. The vast majority of my code runs on Linux, with a small Windows footprint. There is a proprietary project-specific rule in play here that states all system dependencies must be dynamically linked, but all other dependencies not already installed on the systems, which I thankfully don't control, must be static. In other words, I can use boost, poco, mysql++, zeromq, etc, but those have to be linked statically. I also can't create my own DLLs. My Linux brain is guessing that rule is my Windows problem.
I have a large static library as part of the projects with lots of common code linked into other programs. That static library is compiled /MD, which appears to be what I have to do on Windows to dynamically link system libraries. However, I need that library linked into other programs statically. When I add a reference to the library in VS 2017 to other projects, nothing happens and the symbols aren't resolved and I get lots of link errors. To fix that, I hard-coded my library into the various other projects via Linker->Input->Additional Dependencies and that "works" after a fashion, the code links and runs but VS doesn't resolve the static library dependency. While I can go forward with this solution, it's hardly ideal. Rebuilding the solution always results in failure (or links in old code into a new build) because the big static library always takes the longest and none of the other projects know to wait for that build to complete. The workaround is to build the static library first, then build the entire project.
Does anyone better versed in Visual Studio know the best way to proceed?
Can someone help me understand why this got down-voted? This isn't a troll and I'm hardly a student trying to get someone to do my homework, it's a real problem I'm trying to figure out in a professional setting. I thought that was the whole point to stackoverflow?
So this was something simple. When I went to add the reference I didn't actually click on the check box. Robert Andrzejuk's second comment helped, I had read that before but didn't notice the little check box the first time.
On the add a reference page (right click project in solution browser, Add->References...), the check box next to the item has to be selected.
Add reference widget
I am developing a project on C++ which relies on many of third-party libraries (*.lib files and *.h files). I store these libraries in a folder which is not dependant to project, like C:/thirdpartylib. Relative paths is not an option, since it becomes way too long. I have defined connections to libraries in linker setting and in general C++ settings.
But when I pass the project to supervisor he has to reset all paths to libraries to match his environment. We use git, and the project file is being tracked. He stores thirdparty libraries in another way than me.
Is there any way to make a project more portable? Maybe it is possible to store paths in some sort of config files?
As #gaurav says, the way to deal with this in Visual Studio is with property sheets. It's unfortunate that this term is used for two different things in VS, but I guess they just ran out of names (spoiler alert).
These are very powerful, once you learn how they work, and they're just what you need here because they let you define macros, and these macros can in turn be used in the rest of your project to refer to the (volatile) location of your various libraries. This is a trick that everyone who uses VS should know, but it seems that a lot of people don't.
I don't think it's worth me trying to walk you through the mechanics of setting one up here because Microsoft already document it in the Visual Studio help file. Suffice to say, you do it in the Property Manager, that should help you track down the relevant information.
There is also an excellent blog post here which I recommend you read before you do anything else:
http://www.dorodnic.com/blog/2014/03/20/visual-studio-macros/
It's also on Wayback Machine here:
https://web.archive.org/web/20171203113027/http://www.dorodnic.com/blog/2014/03/20/visual-studio-macros/
OK, so now we know how to define a macro, what can we do with it?
Well, that's actually the easy part. If we have a macro called, say, FOO, then wherever we want to expand that macro in some project setting or other we can just use $(FOO). There's also a bunch of macros built into the IDE as listed here:
https://msdn.microsoft.com/en-us/library/c02as0cs.aspx
So, you, I imagine, will want to define macros for the include and lib directories for each of your external libraries and you can then use these to replace the hard-coded paths you are currently using in your project.
And that, I reckon, should sort you out, because the definitions of the macros themselves are stored in a separate file, external to your project file, and different users / build machines can use different files. IIRC, these have extension .props.
Also, you can define a macro in terms of another macro or macros, and that makes the job easier still.
So, who still thinks that Microsoft don't know how to create a build system? Visual Studio is a fantastic piece of software once you get used to it, there's just a bit of a learning curve.
The way to go for large project is to use a package manager. There are some good options out there. Perhaps in windows and visual studio you can use vcpkg or NuGet unmanaged.
If you cannot use a package manager for some reason, the next thing to do is to commit all the dependencies to the GIT repo. If you only target windows platforms like windows 8 or 10 and want to support only VS2017 then committing the compiled dependencies is not a problem. The downside is that the repo will become huge.
For a tiny school project the latter option is viable.
I'm lost here and I have no clue how to proceed. This is not a question about how to make my program work, this is a question about how to stop wasting my time.
My programming environment is Visual Studio 2013 on windows, in C++.
I use 3 libraries extensively, namely: boost (using dynamic linking), OpenCV, and Qt.
During the development, I have configured VS to look at those 3 libraries by default for include and .lib. I have also added the 3 folders containing all the dlls to my PATH environment variable.
It works, but it is sometime painful, let me explain you when.
First hassle: Anytime I have a LNK error telling me I miss a function, it is usually on OpenCV since it has only one include file referencing all the functions. I have to look at OpenCV's source code to see what module this function belongs to and to know what I must link my program to.
Second Hassle: When comes the time to deploy my application, I have to ship it with all the relevant dlls. To know which one I need, I open dependency walker and try to forget nothing, I have then to test it on a different computer because 102% of the time I have missed a couple, and then I have to configure my Installer generator to include all those one by one.
Third Hassle: To ease a little bit the process of configuring a new development machine, I have recently switched to NuGet. It is great, I add boost with a couple of clicks to any project. But now my boost DLLs are everywhere, I have one folder per boost library, and since there are dozens of those I can't even add them all at once to my PATH now, so I have to move them manually to the appropriate folder, and that is really not what I want to do with my not-so-precious-but-who-are-you-to-judge time
I have looked around and couldn't find any good practice regarding this issue, maybe because they are too obvious, or too specific to a particular setup.
How do you do? How would you do if you were me?
We put all our external dependencies in version control along with the code. This ensures that all code can build "out of the box" on any of our development machines and also ensures that for any given version of the code, we know exactly which dependencies is has.
The best way to check for missing dependencies is how have a good automated test suite, if you've got comprehensive converge then if your tests pass you must have deployed the required libraries.
In terms of linking to the appropriate libraries, unfortunately, that just sounds like an issue with the structure of OpenCV (I'm not familiar with OpenCV). I tend to use dumpbin under Windows and nm under Linux to easily grep for symbols when I get link errors with an unfamiliar library.
The situation is the following: I have the source code of one programm (lets call it programA) (written in C and C++), as well as the CMakeLists.txt and CTestConfig.cmake files. I already installed programA using CMake's graphical user interface and, as it is obvious, it worked. It created the .exe file (I'm working on Windows 7 OS).
The problem is that, right now, I've been asked to edit the program (and so, I must be able to edit the code and degugging it as changes are made). I also need to compile it but not in .exe anymore but in .dll so I can add it to a website we have.
I've read in forums that CMake can compile programA into a .dll if I need to, but as I would need to make some changes I consider that CMake debugging is not as useful and easy as using entirely VS. From the little I know from CMake language, the CMakeLists.txt is mainly used to check the OS of the user as well as adding some libraries in case they are not found.
I have to admit I have no idea in programming CMake directives, as I have been working with ASP.NET, C, C++ and C# mostly. Then, my idea is to try to work only in visual studio 2010 instead of using cmake as well, so once I have the program 'adapted' to VS and can be compiled just using VS, I'm ready to start my job. So the question I have is how can I perform the same task CMake did just using Visual Studio (Is there any way of implementing CMake directives in VS?), can VS compile by receiving as an argument something similar to that CMake.txt file (though it needs to be translated into another language)?
To skip the use of CMake I tried to copy the source code into a new project in VS. However as it does not use the CMake directives when compiling, it gives several errors, most of them related to the fact that some headers.h can't be found (cause they might be in a subfolder). And there are so many subfolders to add the paths to the predefined directories of search that it would take ages.
I'm sorry I can't be more precise in my explanation. I'm good at programming little projects on my own, but it's the first time I have to work on other's programm. Please don't hesitate to ask if anything was not properly understood
I would appreciate a lot any suggestion / advice /guidance you can give.
To make a dll, use add_library command and the SHARED keyword
add_library(mylib SHARED ${files})
this is easy with CMake, don't go back in visual that will be harder at the end
The Good News
Fortunately, cmake can generate VS Projects automaticaly for you (this tutorial s specific for OpenTissue, but Steps 1 to 3 should be the same for you).
The [not so] Bad News
Depending on the complexity of the project, VS Projects automaticaly generated by cmake can get pretty nasty, to the point of illegibility. It will, for example, hard link any library dependencies using the specific paths of your machine, so the project will most certainly not be portable across setups. In any case, that's the intended bahavior, because the primary idea of supporting this generator is simply making it work, thus allowing users to easily compile projects using MSVC, so there's not much you can do here. Nonetheless, it should work in your machine and will certainly be a great starting point for you, just create a project yourself from scratch copying the relevant parts out of the automatic generated version.
Currently my visual studio is basically generating Engine.dll and Game.exe
Engine.dll links to some other basic libraries like:
d3dx9d.lib
ComCtl32.lib
WinMM.lib
WSock32.lib
etc.
I also wanted to try to create an Engine.lib, but I get some really nice warnings now: Symbol x has been defined already. These libraries define the same symbols.
So I read somewhere that I must force my user (Game.exe) to link to the libs instead. But this is just really inconvenient I think, especially if I have many games and I decide to add another library to my engine. It's just maintenance for something so simple.
Should I stick to the .dll, or is there some way to fix this beauty up?
Thanks a lot,
Antoon
You need to make up your mind whether the want the DLL or the static link library. Advantage of a DLL is that the build times can be quicker if you make local changes. Advantage of a .lib is that you'll end up with only one deployable file.
Getting it linked (either the static .lib or the dll's import .lib) is otherwise automatic. You want to make sure that the library is built first, can't link the .exe without it. Right-click the exe project in the Solution Explorer window, Project Dependencies, tick the library project. That automatically adds the .lib to the exe project's additional dependencies.
Using #pragma comment(lib, "engine.lib") in the engine's header file is another way. Repeat for other dependencies like the OS import libraries. Getting the library path right is a // todo item.
Did you create a different namespace to avoid naming clashes?
EDIT -- seems like there is some confusion as to what you're asking, because you are asking a couple of questions.
To me, it sounds like you want to take a stab at implementing your own Engine class. However, you've got naming issues. I am treating this as more of an architectural question now. If you write your Game to an interface, then the problem goes away. For example, if your Engine is using different algorithms, then if you had written an EngineInterface that the current Engine and YourEngine implemented, then you could easily use Strategy to flip between the different implementations on the fly. This is nice because you'll be able to see the differences in-game if you wire the preferences into the app.
If the symbols are not supposed to be the same, use diferent names or control how they are exposed. Another option is the usage of namespaces to avoid naming conflicts.
If the symbols are supposed to be the same thing, you need to define those only once in one of the libs.