Re: rust: cargo build-system: how to handle libraries

[David Craven <david@craven.ch>]

> We run (or this is the default) cargo with `--bin`, which is
> necessary for everything which needs to be compiled and features
> a Cargo.toml.

All crates have a Cargo.toml file. The interesting crates are the ones with
a Cargo.lock file.

> To "build" libraries, we have to explicitly tell cargo to not
> run/build/whatever with --bin ?

Building libraries is currently not very useful at the moment, since they are
not meant to be libraries in the C sense, but in the sense that it's a
collection
of source code that can be reused in a rust project. One can create a library
in the C sense, but most crates do not do this and are not intended to be abi
compatible with C.

> Or do I have to interprete what I read a while ago "we just need
> to copy the libraries to the store" as literally "if we encounter
> no Cargo.toml, let's copy everything to the store as is"?

If we encounter no Cargo.lock file it generally means the above.