Note warning of default features on libc

[AtheMathmo]

The default features of libc include libstd. This should be noted on this page.

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[steveklabnik]

Thanks! Agree 100%. It might be nice to show how not to do this as well?

[AtheMathmo]

I'm not sure I understand what you mean by how not to do this? I had considered adding an example of how to do this with cargo but excluded those in the PR.

I'm happy to change it however you see fit. We could make this a slightly larger section with an example of the libc dependency in cargo.toml?

[durka]

Including a sample Cargo.toml seems like a good idea. Also why are there so many hidden lines in the example? Is what rustdoc ends up showing really correct?

[steveklabnik]

The reason they're hidden is that they use the internal libc so that we can run the tests, but not show using the internal libc, because that's not what you're supposed to do.

[steveklabnik]

@AtheMathmo just a typo. I meant how to do it, sorry :( Yeah, a slightly larger section showing a Cargo.toml would be great.

[AtheMathmo]

Before I jump in - should I stick with a quoted note or make a new section? i.e.

Note: Warning about libc default features. Be sure to set default-features=false in your Cargo.toml file.

OR

Warning: Default features in libc

The default features for libc include the standard library that we are trying to exclude. You must explicitly disable these. You can exclude the default features by modifying your Cargo.toml file as follows:

[dependencies.libc]
version = "*"
default-features = false

[steveklabnik]

I'd make it a new section. We sorta assume you know how to include an external crate in the current version of the text, but it might be worth using this to explain that; just saying that we need libc, here's how you include it, and make sure you turn off default features.

Also, using version = "*" is an antipattern, I'd use libc = "0.2.11"

[AtheMathmo]

Thanks for the feedback!

Have added a new section with more details on including libc. Let me know if you want anything added/removed/reformatted.

[steveklabnik]

@bors: r+ rollup

Thanks again!

[bors]

📌 Commit 8844fd4 has been approved by steveklabnik

[bors]

⌛ Testing commit 8844fd4 with merge 4c45d26...

[bors]

☀️ Test successful - auto-linux-32-nopt-t, auto-linux-32-opt, auto-linux-32cross-opt, auto-linux-64-cargotest, auto-linux-64-cross-armhf, auto-linux-64-cross-armsf, auto-linux-64-cross-freebsd, auto-linux-64-cross-netbsd, auto-linux-64-debug-opt, auto-linux-64-nopt-t, auto-linux-64-opt, auto-linux-64-opt-mir, auto-linux-64-opt-rustbuild, auto-linux-64-x-android-t, auto-linux-cross-opt, auto-linux-musl-64-opt, auto-mac-32-opt, auto-mac-64-nopt-t, auto-mac-64-opt, auto-mac-64-opt-rustbuild, auto-mac-cross-ios-opt, auto-win-gnu-32-nopt-t, auto-win-gnu-32-opt, auto-win-gnu-32-opt-rustbuild, auto-win-gnu-64-nopt-t, auto-win-gnu-64-opt, auto-win-msvc-32-cross-opt, auto-win-msvc-32-opt, auto-win-msvc-64-cargotest, auto-win-msvc-64-opt, auto-win-msvc-64-opt-mir, auto-win-msvc-64-opt-rustbuild