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Allow hermit-abi to build without std #103

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Jan 14, 2021
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Allow hermit-abi to build without std #103

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3 changes: 1 addition & 2 deletions hermit-abi/src/lib.rs
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Original file line number Diff line number Diff line change
@@ -1,8 +1,7 @@
//! `hermit-abi` is small interface to call functions from the unikernel
//! [RustyHermit](https://github.com/hermitcore/libhermit-rs).

#![cfg_attr(feature = "rustc-dep-of-std", no_std)]
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I'm fairly sure that this line is needed, since the hermit std library (in the rust compiler) depends on the hermit-abi crate.

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This just removes the cfg_attr so that this crate is always no_std, so things should still work correctly with it being a dep of libstd.

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@jschwe jschwe Jan 14, 2021 •
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AFAIK as of now, it is still necessary to have rustc-dep-of-std in dependencies of std library crates.
There is a plan to remove it (rust-lang/wg-cargo-std-aware#51), but the issue is still open.

This issue is to discuss the strategy for removing the rustc-dep-of-std feature and the rust-std-workspace-* packages which allows standard library crates to use crates from crates.io

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@josephlr josephlr Jan 14, 2021 •
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That is correct, and that feature isn't removed by this PR.

EDIT: All this PR does is remove the gating of no_std based on the rustc-dep-of-std feature. Right now, this crate requires std unless the rustc-dep-of-std feature is enabled, in which case std is not required.

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A sorry, I got confused there for a moment. Thanks for the clarification.

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For example, libc (which is also a dependency of std) is just unconditionally no_std, see: https://github.com/rust-lang/libc/blob/715b50e1555a339d4e474ac4f6ae5a944bc1b180/src/lib.rs#L28

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The current network support depends on std. libstd doesn't select this feature. But we should make sure that this is not enabled if std is not enabled.

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It looks like that support is in a different crate, this crate (hermit-abi) is just a facade crate that doesn't depend on any std code or types.

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I will fix with another PR.

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It looks like that support is in a different crate, this crate (hermit-abi) is just a facade crate that doesn't depend on any std code or types.

Sorry, my mistake. I mixed up hermit-sys and hermit-abi. :-)

#![feature(const_raw_ptr_to_usize_cast)]
#![no_std]
extern crate libc;

pub mod tcplistener;
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