How do two different programing language communicate with each other specifically?

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blablahblah@reddit

How it works depends on the language. Sometimes, the languages compile to the same thing so even though the source code looks different, if you're using Java and Kotlin or C# and Visual Basic, one language can just use the other's functions and types as if they were written in the same language. Other times, there's a specific convention in one language for how to reference things in another language. This is called a foreign function interface. You see it most often with C because C is so old and has a well defined, unchanging way that functions are compiled. And the third way is the one you know- send bytes to another program in a defined format like json or xml and deserialize it on the other side. If you want to make it easy to define the types and methods in multiple languages at once, you can use an interface definition language like Google's protocol buffers, which can then be used you generate functions and type definitions in a number of supported programming languages.

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Shot_Culture3988@reddit

For getting languages to talk to each other, middleware or brokers usually do the trick. You could try protocol buffers (protobuf) or Apache Thrift for this job. These aren't just about JSON; they can handle complex data types across languages. The key is in how well they abstract away the language differences and get the job done. I've seen folks use gRPC for polyglot microservices too. [APIWrapper.ai](http://APIWrapper.ai) might also come in handy in bridging different systems. It's all about finding the right tool that suits your specific needs and setup.

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TapEarlyTapOften@reddit

System verilog does this with C too. It's pretty incredible that a hardware verification language that has no concept of memory allocation can farm out its work to C.

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Gtantha@reddit

>C# and Visual Basic, one language can just use the other's functions and types as if they were written in the same language. To add to that: C++/CLI. Parts of that C++ code compile to native C++ (if desired), parts to .net and then there are sections where the two can interoperate and the .net code can use the native types and functions like managed code. And both things can happen in the same file. This unholy abomination lets you write a C# UI, call the managed C++ and have that call into native C++ without having to go to p/invoke. Or go in the other direction and write some native c++ that calls into C#, for whatever reason one might do that.

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MisterGerry@reddit

I agree, this is probably the most accurate answer. Languages can be compiled into byte code, machine code or interpreted, which leads to different solutions to calling functions in another language. Some languages are virtually interchangeable and you can mix two languages in the same project, while others are very different and may not even be possible without a hack. The best answer is to know which specific two languages you want to use and look up that specific solution.

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pintonium@reddit

Mostly it's through that JSON data. You have some function that transforms your languages data structures into the JSON format ( typically called serialization) and then a separate function that does the opposite.

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regular_lamp@reddit

This gave me the twitches and made me feel old. I'm sure this is true in web development or whatever (wherever people talk about "stack" but don't mean the data structure). Most compiled languages certainly don't interact this way. Deep down everything eventually uses a C related ABI.

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Frolo_NA@reddit

foreign function interface is one way https://en.wikipedia.org/wiki/Foreign_function_interface sockets are another. writing to shared memory is another.

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HomoColossusHumbled@reddit

First, decide on what you want to communicate, the shapes and names of the data, etc. Is it a list, what are the variables, how big are the string values, and so forth. Then then within each application you create client/server code to send requests or to respond to them. A good deal of application code will go towards translating back and forth between the common share object spec and then whatever internal representations you have for the data. Rhis process involves a lot of planning in advance, and then usually revisions as you discover use cases you hadn't anticipated. It can help to use a standard protocol for defining the API spec, which then gets implemented in both applications. I've used Protobuf for this before.

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dswpro@reddit

The languages don't communicate. The applications each adopt an agreed upon "protocol". This means developers using the language of their choice, write an application that shares data in a specific manner . You use a protocol every day with your browser, the HTTP or hypertext transfer protocol. The language you may be typing code in, gets parsed, interpreted, or compiled into op-codes a processor can execute. It's not like your python program sends python text across the internet for a separate system to interpret, though that's an interesting thought. The protocol is a set of rules each system or application can interpret to call, fetch, store data and invoke operations on a far away computer with programs written in a completely different language.

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Oleplug@reddit

Not all true. I have worked on OpenVMS for years. Every programming language the compiles on that platform uses the same 'calling' standard. C calling COBOL, PASCAL, FORTRAN, BASIC is normal. There are system services written in macro assembler or DEC's BLISS called from any supported language on VMS. Have used PHP modules using COBOL shared images to do the work.

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lekkerste_wiener@reddit

You don't share specific data structures designed for specific languages, you share just the data. You can define a protocol that both will follow for that. As for how, there are ways. sockets, queues or streams, fifos, you choose.

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CommanderUgly@reddit

The first language would need to export data at an API endpoint in a format the second language could interpret. JSON is handy for this.

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taedrin@reddit

You use a shared contract and a common protocol to communicate that contract between the programming languages. The shared contract might be something like a JSON or XML schema (whether explicitly declared or implied by simple agreement), or something more primitive like a simple function/method signature. The common protocol might be web based like REST or SOAP, or more primitive like a [calling convention](https://gcc.gnu.org/onlinedocs/gcc/x86-Function-Attributes.html). For primitive communication between programming languages within the same program, library authors will frequently publish [bindings](https://en.wikipedia.org/wiki/Language_binding) that make it easy to consume the library in another language. The binding/wrapper provides you with the function/method signatures as well as stubbed implementations which use the correct calling convention to invoke the correct function/method in the library, and to return the appropriate data to the caller in a format that the caller understands. If there are no bindings published for the language you wish to use, you can still write one yourself - but it requires you to figure out the method/function signatures as well as calling conventions yourself.

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ConcreteExist@reddit

Languages don't "talk" to each other, programs do, and they do so by leveraging APIs and serializing information into a format that either program can reason about. So one program might speak to another by sending JSON text in an HTTP requestion, other might make an RPC call to another program and send the data as a series of primitives in a bytestream. How, exactly, is up to the developer(s) writing the individual program(s).

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Quillox@reddit

This will interest you: https://www.enterpriseintegrationpatterns.com/

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Roguewind@reddit

I think you need to adjust your definition of what an API is. API means application programming interface - or the way to talk to an application. All programming languages are just text, and in one language you use different commands to do the same thing from one language to another. An API is just the definition of how you communicate. For instance, there’s php-mysqli which is a program that runs in php and provides a way to send data to a mysql db. The syntax you use to do this is the API. There are other ways to do this with node, C#, Java, etc. Each has its own api.

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aanzeijar@reddit

Web APIs with json data are already language agnostic. All languages can read and generate json - which is why it's used so often for web. If you mean on the same machine in the same program, that is usually called [Foreign Function Interface](https://en.wikipedia.org/wiki/Foreign_function_interface) or for short FFI. It's mostly used to call libraries written in C from other languages, but it can also be used with other languages as targets. Beware though, C data structures are kinda the lingua franca between different languages, so any higher level information may get lost or require serious hacks to work around.

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gyroda@reddit

The term API exists outside of web services. One language can have an API that other languages can use. To contrast this, lower level systems often have ABIs (application binary interfaces). An ABI doesn't have friction calls so much as "put a value in this address in memory and/or jump to this memory address". A really common example of two languages talking to eachother is Python and C. Python is very easy to use but not very fast, so many of the performance-focused libraries like NumPy have the number crunching written in C and the python code calls the C code. There's a guide on that here https://realpython.com/python-bindings-overview/ Another example: every single web browser that supports web assembly (WASM) does this; certain things can't be done in WASM so you need to be able to run JavaScript from your WASM code. The browsers provide an API for this. If you want to communicate between two different running programs there are a variety of message passing methods out here.

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bravopapa99@reddit

XML, SOAP, ASN.1... and JSON. There are many ways. It's just bits over the wire by agreement.

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How do two different programing language communicate with each other specifically?

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20 Comments

blablahblah@reddit

Shot_Culture3988@reddit

TapEarlyTapOften@reddit

Gtantha@reddit

MisterGerry@reddit

pintonium@reddit

regular_lamp@reddit

Frolo_NA@reddit

HomoColossusHumbled@reddit

dswpro@reddit

Oleplug@reddit

lekkerste_wiener@reddit

CommanderUgly@reddit

taedrin@reddit

ConcreteExist@reddit

Quillox@reddit

Roguewind@reddit

aanzeijar@reddit

gyroda@reddit

bravopapa99@reddit