https://DevOpsCloud.io -- Cloud Monk Losang Jinpa, Ph.D., MCSE/MCT, GitOps DevOps Engineer

Return to Ruby, Foreign Function Interface (FFI)

Ruby FFI (Foreign Function Interface) is a gem for Ruby that allows the execution of code written in other languages, such as C, directly from Ruby programs. It provides a way to dynamically load libraries, access their functions, and define custom data types. Ruby FFI eliminates the need for writing C extensions in Ruby and simplifies the process of interfacing with external libraries.

• **Dynamic Library Loading:** Ruby FFI can load shared libraries at runtime, making it flexible and adaptable to different environments.
• **Function Binding:** It allows defining and binding to functions in the loaded libraries, specifying argument types and return values.
• **Custom Data Types:** Ruby FFI enables the creation of custom data types that mirror structures and unions in the C libraries.
• **Memory Management:** It handles memory allocation and deallocation for interacting with C data structures.
• **Callbacks:** FFI supports passing Ruby procs or blocks as callback functions to C libraries.
• **Platform Independence:** It is designed to work on multiple platforms, including Windows, macOS, and Linux.

• **GitHub Repository:** s://github.com/ffi/ffi(https://github.com/ffi/ffi)
• **RubyGems:** s://rubygems.org/gems/ffi(https://rubygems.org/gems/ffi)
• **Official Documentation:** [invalid URL removed]

```ruby require 'ffi'

module MyLib

 extend FFI::Library
 ffi_lib 'mylib.so'

 # Define function signature
 attach_function :add, [:int, :int], :int

1. Call the C function

result = MyLib.add(5, 3) puts result # Output: 8 ```

In this example, `ffi_lib` loads the shared library `mylib.so`, `attach_function` defines the `add` function with its argument and return types, and then the `add` function is called directly from Ruby.