Generally, Rust dependencies have two types of linking:
- Static: Via the rlib format.
- Dynamic: Via shared libraries (.so or .dll).
The preference—if a corresponding rlib can be found—is to link statically and therefore include all dependencies into the output binary, making the file a lot larger (to the dismay of embedded programmers). Therefore, if multiple Rust programs use the same dependency, each comes with its own built-in version. It's all about the context though, since, as Go's success has shown, static linking can simplify complex deployments since only a single file has to be rolled out.
There are drawbacks to the static linking approach beyond size: for static libraries, all dependencies have to be of the rlib type, which is Rust's native package format, and cannot contain a dynamic library since the formats (for example, .so (dynamic) and .a (static) on ELF systems) aren't convertible.
For Rust, dynamic linking...
