The C ABI

 The C ABI refers to the C Application Binary Interface.

This will differ depending on platform.

Platform specific ABI specifications include:

x64 ABI Conventions

ABI for Unix/Linux

Very important for C/C++ and assembly programmers.

Rust uses C++

Tales of the end of C++ are greatly exaggerated. 

Rust uses C++ in the form of LLVM which is built in C++. Sure, the Rust compiler (rustc - which was initially OCaml'd and rewritten in Rust) is mostly Rust with some legacy bits in C++, but the backend (LLVM) used for code generation is C++ code. 

The standard library has some C bindings too, but that's by the by.

TCPL Still Rules the Linux Roost

The programming language C (born in the 1970s, created by Dennis Ritchie, who also created its predecessor, B) still rules the roost as far as the Linux kernel is concerned, whereby of 37 million lines of code, we have just over 35m LOCs written in C as per analysis from OpenHub.

Linux is the open source version of Unix, which was written in C, and prior to that in assembler. The introduction of the programming language C made the code portable to different hardwares.

Ken Thompson and Dennis Ritchie and their colleagues at Bell Labs (AT&T) were the co-creators of the Unix Operating System, created in 1969.   Douglas McIlroy introduced the Unix philosophy of small, composable tools. Brian Kernighan helped to popularise UNIX and C through co-authoring The C Programming Language with Dennis Ritchie.