Currently I am using a hardware that provides me a software package that comes from a DLL. They also provide packages in different languages (Java, C++ and Python) with functions from the DLL, so I am programming my app in Java. I would like to change to Ada but I don't know the way to use the DLL functions or the packages that the company offer me in other languages. Is there a way to do it?
I know I can extract the function names from the DLL, but I don't exactly know how to convert that into an Ada package, or if I can use the packages already made in other languages in any way.
The lazy answer is simply "yes". :-)
The GCC documentation on the subject is here: https://gcc.gnu.org/onlinedocs/gnat_ugn/Using-DLLs-with-GNAT.html
As it says, you also need an Ada specification for the functions in the DLL, you want to use. You can either write it by hand, or use gcc -fdump-ada-spec on the C or C++ header files to have one generated automatically. The generated specifications are not always beautiful, but they are more likely to be correct than something you write from scratch yourself.
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I want to bind a different programming language to the Godot game engine. Is there an instructional document or video on this topic? For example, how was this project done: godot-rust. If I can learn the basics, I can succeed in working in a different language. Thanks.
In this answer I show you the different approaches to add language support in Godot 3.x (the situation will be somewhat different with Godot 4.0 and GDExtension - which replaces GDNative and hopefully means less custom builds), and I mention some languages that are supported by each of these approaches. However, this is not an exhaustive list of the languages.
First of all, Godot has official build-in support for GDScript and Godot's VisualScript (and Godot's shading language and its visual counterpart if those counts for you).
There are a few ways to use C++:
You can use it to create GDNative scripts (which are basically a wrapper around native calls that allow you to use them as scripts in Godot).
Or you can create modules (which are static libraries you can add in a custom Godot build).
And since Godot source is in C++, you don't have to restrict yourself to making modules if you are making custom builds.
In web builds Godot can interface with JavaScript via the JavaScript class. However, this approach does not allow you to add JavaScript scripts to Nodes, and so on.
Then there are languages that can only be added in custom builds of Godot, which is currently the official support for C#.
There are other non-official custom builds that offer language binding for languages such as Lua, Kotlin, TypeScript and JavaScript (this time allowing you to make scripts).
If you need to add a runtime, you would probably do this.
Some language take advantage of the fact that Godot's has official Mono support in order to support C#. This way you can, for example, use F# and Clojure.
They start by adding a C# project and then modify it so it uses another language. This is viable if your language already compiles to .NET.
Some other languages can be added as plugins that implement the PluginScript class via GDNative. This is the case of Python and Lua (again) which you can get from the asset library.
This is the most user friendly way to add language support to Godot, but it is limited to what you can do with PluginScript.
Addendum: Gil Barbosa Reis, author of the aforementioned Lua bindings, has an article series about its implementation stuffed away in the repository (in English and Portugueses): godot-lua-pluginscript/extras/articles/. It is probably the most comprehensive tutorial to date.
Other languages are added by means of taking advantage of GDNative (They basically mimic what you would do with C++). This is the case of Nim, Rust, D, Haskell, Go, Swift…
So that's how godot-rust works: make native libraries using rust and the godot-rust create and add them as if they were made in C++. For any language for which there are the means to make native libraries already, this is a good option.
Finally there is another way to add support for a language: a transpiler from that language to GDScript, which can be automated with an addon that might also be written in GDScript. This is the case of Lisp.
This last approach is mostly used for domain specific languages.
The official docs here provide your answer:
Godot officially supports GDScript, C/C++, C#.
Some 3rd party languages that can be used are: Rust, D, Python, Nim, and Go.
Background: I want to develop a component therefore building a class library.
This component should be usable with many higher-order languages such as C, C#, C++, VB, Java, Haskell, Ruby, Erlang, ...
I do not want to exclude any users which are not using my development language.
Are there principles or tools which supports my project?
I searched a little bit and found Haxle for compiling into different languages, but it supports very few of them.
I would even develop parallel in all n languages to be supported, but if I want to change or fix something I have to maintain all other n-1 and the code is possibly distributed...
This is not what I know about clean code design and maintainability. So how to manage edits on code for the different languages?
What is the proper way to solve this? I am surely not the first one which want to build a library for multiple languages.
I want to develop this library (in this case for complexity reduction) in one target language but this time for multiple platforms (Unix, Win, Mac ...).
How to manage this? In fact there will be appreciated about 90% of code which is platform independent and 10% which differs for every OS.
What is the best way to control the changes in the platform dependent code? (The independent is easy ...)
What if I change so things in the part which uses Unix dependent code, then I have to trail all other platform and the code is possibly distributed.
I think #IFDEF is no option ...
Are there any experiences or hints?
I would be delighted if there are existing solutions to these problems, which are quite similar.
What you want is only possible if you provide interfaces for every language you want to support. Some kind of wrapper which transforms between the client language and ypu library.
This is possible but not practical in most cases for standalone libraries.
Take a look at webservices or or message orientad middleware. In this case your application will be provided within a special container which itself provides interface mechanism e.g.
SOAP, XML-RPC to call your application.
For 1), I would use an interface that all these languages can use. A common approach is something based on networking/TCP, like protobuffer, REST, SOAP. Many languages support these in their standard libraries, and interfaces designed with that are normally language agnostic.
There are basically two options - you could develop a network server or you could develop a JVM-based library which could be shared between some of the JVM languages like JRuby or Jython.
Update from #millimoose: you could also develop your library in C and create bindings for all other languages.
For multi-language:
I thought about TCP/middleware/webservices/REST/ which seems to be the recommended proceeding.
But I think it's all to much at runtime for only using a library.
Also the functionality is a little bit time-critical and so direct procedure calls are more fitting (instead of networking even on localhost). And the library user hasn't to construct an access component only to use the library functions.
So I think the way to go seems to be developing the library in a core language which is widely supported (C/C++, ...) and provide wrapper interfaces for the different target languages.
For multi-platform (mono-language):
No real answer has been provided also not in my mind.
Of course I could simply use Java (what I am familiar with) but what about other languages?
I am surely not the first one having this/these problem(s) ...
We'd like to offer a compiled library that implement a protocol layer to be imported into C/C++ source code project for microcontrollers. And eventually expose a sort of compiled function to the source code project. let's say a sort of "dll". Is there any know technique to realize something of similar?
While it is possible to provide functions via a library, generally in the microcontroller/embedded realm it quickly becomes impractical.
Each microcontroller core will have a unique instruction set. Further, micros from the same family may have a variety of extensions which are either supported or not... So you're left with providing a library file for each individual microcontroller (from each vendor) that you'd like to support.
But...
In my experience, calling conventions between compilers are not the same. So a library compiled by one toolchain will not be able to be linked to object files created by another toolchain.
That leads you to then provide a library for each individual micro from each vendor for each toolchain someone might use. Ick. Oh, and don't rely on an OS calls either, as you don't know what you'll be linked with...
A more conventional approach is to use the same approach RTOS vendors tend to use: provide the source, and protect your IP with licensing terms. The reality is that if your end users want to, they can step through the assembly and figure out exactly what is happening, so you're not hiding your implementation that carefully anyway.
I am using matlab 2009 -- I have .m file.
I want to convert it to dll file so i can use it in c++.
how can I do that, someone told me to use the matlab compiler and is it free?
First you need the compiler. Available from Mathworks here. Also, the compiler is not free for most people, a student version is available when bundled with other Mathworks products.
Mathworks provides a 'Free MATLAB Compiler Interactive Kit' which provides walkthroughs covering the DLL and executable build process.
Another option is to use MATLAB's C/C++ API to convert your source code to C++. All MATLAB's functions are accessible, but it's a pain to write this without good wrappers. It might be worth your while to purchase the compiler.
I've been working non-stop for the last three days on a completely managed interface to Erlang. At this point, I've decided that there simply must be an easier way. I've got a little over 3000 lines and it's not even in a compilable state yet. To be honest, I'm getting lost in my own code.
So, I then remembered that Erlang has a C library called erl_interface. Unfortunately, it only comes as a .LIB file, which isn't usable via P/Invoke. I'm now investigating ways to expose the static library through a DLL.
I'd like to stay away from Visual C++, mostly because I'm not a C/C++ programmer by nature and I find it really difficult to configure. TinyC is my compiler of choice when working with anything in C.
How can I go about this?
I know I can link erl_interface to a DLL, but how can I expose the functions? Do I have to essentially wrap each and every one of them in my own exports? That probably won't be a problem, since I could write a script to generate the code from the header file. But is there an easier way that I just don't know about?
Also, please don't recommend OTP.NET. It's a nice library, but I'm looking to use this is a large project, so I'd like to keep it in-house.
So, your problem is one of turning a static lib into a dynamic one.
The least-effort solution would be to write a thin shim file in 'C', that just delegates to the files in the .lib e.g.
ReturnType my_method1(args...) {
return real_method1(args...);
}
...
and build a DLL from that and the static lib.
Afterthought -- There is another approach you could take -- which is build the .lib into a C++/CLI assembly and do the transition/wrapping in that. It's what C++/CLi is there for, after all.
If you want some help with interfacing to Erlang with C, have a look at "EPAPI" (Erlang Port API) link text. You can of course browse the source code since it is hosted on Google Code. A DEBIAN repository is also available.