squiid/rust
1
0
Fork 0
Code Issues Pull requests Projects Activity

Document unstable --extern options

Browse source 
Co-Authored-By: Joshua Nelson <github@jyn.dev>
Co-Authored-By: Eric Huss <eric@huss.org>
This commit is contained in:
Chris Denton 2022-06-18 11:20:53 +01:00
parent ff86b27e7b
commit c20e0e1e8e
No known key found for this signature in database
GPG key ID: 713472F2F45627DE
1 changed files with 22 additions and 0 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

22
src/doc/unstable-book/src/compiler-flags/extern-options.md Normal file
View file

@ -0,0 +1,22 @@
# `--extern` Options
The behavior of the `--extern` flag can be modified with `noprelude`, `priv` or `nounused` options.
This is unstable feature, so you have to provide `-Zunstable-options` to enable it.
## Examples
Use your own build of the `core` crate.
`rustc main.rs -Z unstable-options --extern noprelude:core=libcore.rlib`
To use multiple options, separate them with a comma:
`rustc main.rs -Z unstable-options --extern noprelude,priv,nounused:mydep=mydep.rlib`
## Options
* `noprelude`: Do not add the crate to the external prelude. If used, it will need to be imported using `extern crate`.
This is used by the [build-std project](https://github.com/rust-lang/wg-cargo-std-aware/) to simulate compatibility with sysroot-only crates.
* `priv`: Mark the crate as a private dependency for the [`exported_private_dependencies`](../../rustc/lints/listing/warn-by-default.html#exported-private-dependencies) lint.
* `nounused`: Suppress [`unused-crate-dependencies`](../../rustc/lints/listing/allowed-by-default.html#unused-crate-dependencies) warnings for the crate.