### Example Checksum Generation Command

Source: https://github.com/philss/rustler_precompiled/blob/main/PRECOMPILATION_GUIDE.md

Specific example of the checksum generation command for RustlerPrecompilationExample.Native.

```bash
mix rustler_precompiled.download RustlerPrecompilationExample.Native --all --print
```

--------------------------------

### Mix.exs Package Configuration

Source: https://github.com/philss/rustler_precompiled/blob/main/PRECOMPILATION_GUIDE.md

Example of the 'files' configuration in mix.exs to include necessary files for a Hex package, including the checksum file.

```elixir
defp package do
  [
    files: [
      "lib",
      "native/my_nif/.cargo",
      "native/my_nif/src",
      "native/my_nif/Cargo*",
      "checksum-*.exs",
      "mix.exs"
    ],
    # ...
  ]
end
```

--------------------------------

### Define Build Matrix for Targets

Source: https://github.com/philss/rustler_precompiled/blob/main/PRECOMPILATION_GUIDE.md

Specify the build matrix for GitHub Actions to compile NIFs for various operating systems, architectures, and NIF versions. This example targets Linux, macOS, and Windows for x86_64 and aarch64 architectures, using NIF version 2.15.

```yaml
matrix:
  nif: ["2.15"]
  job:
    - { target: aarch64-unknown-linux-gnu   , os: ubuntu-22.04 , use-cross: true }
    - { target: aarch64-apple-darwin        , os: macos-15      }
    - { target: x86_64-apple-darwin         , os: macos-15-intel }
    - { target: x86_64-unknown-linux-gnu    , os: ubuntu-22.04  }
    - { target: x86_64-unknown-linux-musl   , os: ubuntu-22.04 , use-cross: true }
    - { target: x86_64-pc-windows-gnu       , os: windows-2022  }
    - { target: x86_64-pc-windows-msvc      , os: windows-2022  }
```

--------------------------------

### Configure Rustler NIF Versions in Cargo.toml

Source: https://github.com/philss/rustler_precompiled/blob/main/TROUBLESHOOTING.md

Specify Rustler NIF versions in your `Cargo.toml` by disabling default features and enabling specific NIF version features. This example shows how to enable NIF version 2.15.

```toml
[dependencies]
rustler = { version = "0.37", default-features = false }

# And then, your features.
[features]
default = ["nif_version_2_15"]
nif_version_2_15 = ["rustler/nif_version_2_15"]
nif_version_2_16 = ["rustler/nif_version_2_16"]
nif_version_2_17 = ["rustler/nif_version_2_17"]
```

--------------------------------

### Configure 'musl' ABI Targets in Cargo.toml

Source: https://github.com/philss/rustler_precompiled/blob/main/TROUBLESHOOTING.md

Add this configuration to your `.cargo/cargo.toml` file to support 'musl' ABI targets like 'x86_64-unknown-linux-musl' by disabling static linking.

```toml
# This is needed for "musl". See https://github.com/rust-lang/rust/issues/59302
[target.x86_64-unknown-linux-musl]
rustflags = [
  "-C", "target-feature=-crt-static"
]
```

--------------------------------

### Link libatomic for 32-bit ARM Builds

Source: https://github.com/philss/rustler_precompiled/blob/main/TROUBLESHOOTING.md

Configure your `.cargo/config.yml` to link 'libatomic' for 32-bit ARM targets like 'arm-unknown-linux-gnueabihf', as required by some architectures.

```toml
# Libatomic is needed for 32 bits ARM.
# See: https://github.com/philss/rustler_precompiled/issues/53
[target.arm-unknown-linux-gnueabihf]
rustflags = [
  "-l", "dylib=atomic"
]
```

--------------------------------

### Release Profile Configuration

Source: https://github.com/philss/rustler_precompiled/blob/main/PRECOMPILATION_GUIDE.md

Configures the release profile for Rustler projects to optimize build size and compilation time.

```toml
[profile.release]
lto = true
```

--------------------------------

### Generate Checksum File Command

Source: https://github.com/philss/rustler_precompiled/blob/main/PRECOMPILATION_GUIDE.md

Command to generate a checksum file for downloaded NIFs. This file is mandatory for Hex package distribution.

```bash
mix rustler_precompiled.download YourRustlerModule --all --print
```

--------------------------------

### Configure Cargo for Musl Target

Source: https://github.com/philss/rustler_precompiled/blob/main/PRECOMPILATION_GUIDE.md

Provide additional configuration for the Rust compiler in `.cargo/config.toml` when targeting the `x86_64-unknown-linux-musl` platform. This specific configuration is needed to resolve issues related to static linking.

```toml
# This is needed for "musl". See https://github.com/rust-lang/rust/issues/59302
[target.x86_64-unknown-linux-musl]
rustflags =
  [
    "-C", "target-feature=-crt-static"
  ]

```

--------------------------------

### RustlerPrecompiled Module Configuration

Source: https://github.com/philss/rustler_precompiled/blob/main/PRECOMPILATION_GUIDE.md

Defines the RustlerPrecompiled module with essential configuration like OTP app, crate name, base URL, and version. Force build option is available via environment variable.

```elixir
defmodule RustlerPrecompilationExample.Native do
  version = Mix.Project.config()[:version]

  use RustlerPrecompiled,
    otp_app: :rustler_precompilation_example,
    crate: "example",
    base_url:
      "https://github.com/philss/rustler_precompilation_example/releases/download/v#{version}",
    force_build: System.get_env("RUSTLER_PRECOMPILATION_EXAMPLE_BUILD") in ["1", "true"],
    version: version

  # When your NIF is loaded, it will override this function.
  def add(_a, _b), do: :erlang.nif_error(:nif_not_loaded)
end
```

--------------------------------

### Configure GitHub Actions Permissions

Source: https://github.com/philss/rustler_precompiled/blob/main/PRECOMPILATION_GUIDE.md

Set write permissions for contents, id-token, attestations, and artifact-metadata in your GitHub Actions workflow file. This is necessary for creating releases and optionally for using artifact attestations.

```yaml
permissions:
  # For creating a new release.
  contents: write
  # The following are needed for the "actions/attest" GH Action.
  id-token: write
  attestations: write
  artifact-metadata: write
```

--------------------------------

### Add Rustler Precompiled to Mix Dependencies

Source: https://github.com/philss/rustler_precompiled/blob/main/README.md

Add `rustler_precompiled` to your project's dependencies in `mix.exs`. This is typically an optional dependency used during development.

```elixir
def deps do
  [
    {:rustler_precompiled, "~> 0.9"}
  ]
end
```

--------------------------------

### Specify a Single Rustler NIF Version in Cargo.toml

Source: https://github.com/philss/rustler_precompiled/blob/main/TROUBLESHOOTING.md

Declare your Rustler dependency to explicitly use a specific NIF version, such as '2.16', by including it in the `features` list.

```toml
[dependencies]
rustler = { version = "0.37", default-features = false, features = ["nif_version_2_16"] }
```

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