Closed
Description
CMSG_SPACE is supposed to be a const function. It was, until PR #4105. Now, nix fails to build with the libc-0.2 branch. It fails for both x86_64-unknown-linux-gnu and x86_64-unknown-freebsd. I bisected the regression to verify that it really was #4105.
Steps to reproduce:
$ git clone git@github.com:nix-rust/nix.git
$ cd nix
$ sed -I "" 's!version = "0.2.164"!git = "https://github.com/rust-lang/libc.git", rev = "ae052d3b6a045d58b7ef3187a94de81695e2591e"!' Cargo.toml
$ cargo check --all-features
Updating crates.io index
Updating git repository `https://github.com/rust-lang/libc.git`
Locking 54 packages to latest compatible versions
Adding sysctl v0.4.6 (available: v0.6.0)
Compiling autocfg v1.4.0
Compiling libc v0.2.164 (https://github.com/rust-lang/libc.git?rev=ae052d3b6a045d58b7ef3187a94de81695e2591e#ae052d3b)
Compiling cfg_aliases v0.2.1
Checking cfg-if v1.0.0
Checking pin-utils v0.1.0
Checking bitflags v2.6.0
Compiling nix v0.29.0 (/tmp/nix)
Compiling memoffset v0.9.1
error[E0015]: cannot call non-const fn `CMSG_SPACE` in constant functions
--> src/sys/socket/mod.rs:652:14
|
652 | unsafe { libc::CMSG_SPACE(mem::size_of::<T>() as libc::c_uint) as usize }
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
For more information about this error, try `rustc --explain E0015`.
error: could not compile `nix` (lib) due to 1 previous error