Dynamic Libraries

Letting C call Rust does not mean exposing ordinary Rust functions directly to C.

C understands C ABI: symbol names, calling conventions, integers, pointers, struct layout, memory ownership, release functions, and error returns. Rust internals such as String, Vec, Result, traits, and panic should not cross the C boundary directly.

A stable model is:

C call
-> extern "C" wrapper
-> validate pointer and length
-> convert to safe Rust types
-> call internal Rust logic
-> convert result to C-compatible return values

This article covers C calling Rust. Rust calling C comes next.