https://github.com/hzeller/nix-bazel-with-clang
Documenting an issue using clang with bazel in nix
https://github.com/hzeller/nix-bazel-with-clang
Last synced: 3 months ago
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Documenting an issue using clang with bazel in nix
- Host: GitHub
- URL: https://github.com/hzeller/nix-bazel-with-clang
- Owner: hzeller
- Created: 2023-02-12T19:06:39.000Z (over 2 years ago)
- Default Branch: main
- Last Pushed: 2023-02-12T19:42:56.000Z (over 2 years ago)
- Last Synced: 2025-05-21T11:13:25.758Z (5 months ago)
- Language: C++
- Size: 2.93 KB
- Stars: 0
- Watchers: 2
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
Awesome Lists containing this project
README
Compilation in clang stdenv in nix.
-----------------------------------
Git repo accompanying iseue
https://github.com/NixOS/nixpkgs/issues/216047
This small example project does not compile with with clang stdenv.
This is the [shell.nix](./shell.nix) used in this example project, allowing
to choose between regular and clang stdenv.
```nix
{ pkgs ? import {} }:
let
#used_stdenv = pkgs.stdenv; # this works, using gcc
used_stdenv = pkgs.clang13Stdenv; # this is broken, using clang
in
used_stdenv.mkDerivation {
name = "Testing c and c++ compilation";
buildInputs = with pkgs;
[
bazel_4
];
}
```
Clone this repo and run with
```bash
git clone https://github.com/hzeller/nix-bazel-with-clang
cd nix-bazel-with-clang
nix-shell --command 'bazel clean ; bazel build //... && bazel-bin/main'
```
This results in this build
### With used_stdenv = pkgs.clang13Stdenv
```console
$ bazel clean ; bazel build //... && bazel-bin/main
INFO: Starting clean (this may take a while). Consider using --async if the clean takes more than several minutes.
INFO: Analyzed 2 targets (15 packages loaded, 63 targets configured).
INFO: Found 2 targets...
ERROR: /home/testuser/src/my/bazel-with-clang/BUILD:13:10: Compiling main.cc failed: (Exit 1): clang failed: error executing command /nix/store/i973rwv7n9pq74iac8jlly9s3xlrr0bc-clang-wrapper-13.0.1/bin/clang -U_FORTIFY_SOURCE -fstack-protector -Wall -Wthread-safety -Wself-assign -Wunused-but-set-parameter -Wno-free-nonheap-object ... (remaining 25 argument(s) skipped)
Use --sandbox_debug to see verbose messages from the sandbox
main.cc:1:10: fatal error: 'iostream' file not found
#include
^~~~~~~~~~
1 error generated.
INFO: Elapsed time: 0.216s, Critical Path: 0.03s
INFO: 12 processes: 11 internal, 1 linux-sandbox.
FAILED: Build did NOT complete successfully
```
### With used_stdenv = pkgs.stdenv
Compiling with the default stdenv (change the comments in `shell.nix`) works
```console
$ bazel clean ; bazel build //... && bazel-bin/main
INFO: Starting clean (this may take a while). Consider using --async if the clean takes more than several minutes.
INFO: Analyzed 2 targets (15 packages loaded, 62 targets configured).
INFO: Found 2 targets...
INFO: Elapsed time: 0.903s, Critical Path: 0.16s
INFO: 12 processes: 6 internal, 6 linux-sandbox.
INFO: Build completed successfully, 12 total actions
in C function foo() -> 42
in C++ function bar() -> 42
== SUCCESS ==
got values 42 and 42
```