Target Metadata (OS_PLATFORM, OS_ARCH, OS_IS_UNIX, OS_IS_POSIX)

Silk exposes a small set of compiler-provided target metadata values to both runtime code and Formal Silk (compile-time verification).

These values let programs adapt to the compilation target (platform/OS and CPU architecture) without requiring environment-specific runtime queries.

Notes#

• target metadata is available as built-in compile-time constants in every module:
• OS_PLATFORM, OS_ARCH, OS_IS_UNIX, OS_IS_POSIX.
• the standard library re-exports these via std::os (os).

Built-In Constants#

The compiler provides the following built-in constants in every module:

• OS_PLATFORM: string
• OS_ARCH: string
• OS_IS_UNIX: bool
• OS_IS_POSIX: bool

These behave like normal const values:

• They do not require an import.
• They may be used anywhere an expression of the corresponding type is allowed.
• They are compile-time constants (their values are fixed at compile time and are embedded into the output artifact).

OS_PLATFORM#

A canonical target platform/OS name string.

Current compiler target set and values:

• linux-x86_64, linux-x86_64-musl, linux-aarch64, and linux-aarch64-musl:
• OS_PLATFORM == "linux"
• macos-x86_64 and macos-aarch64:
• OS_PLATFORM == "macos"
• ios-aarch64, ios-simulator-aarch64, and ios-simulator-x86_64:
• OS_PLATFORM == "ios"
• android-aarch64:
• OS_PLATFORM == "android"
• windows-x86_64 and windows-aarch64:
• OS_PLATFORM == "windows"
• wasm32-unknown-unknown:
• OS_PLATFORM == "unknown"
• wasm32-wasi:
• OS_PLATFORM == "wasi"
• amdgcn-amd-amdhsa-gfx942, amdgcn-amd-amdhsa-gfx1100, and amdgcn-amd-amdhsa-gfx1151:
• OS_PLATFORM == "amdhsa"

OS_ARCH#

A canonical target CPU architecture name string.

Current compiler target set and values:

• linux-x86_64, linux-x86_64-musl, macos-x86_64, ios-simulator-x86_64, and windows-x86_64:
• OS_ARCH == "x86_64"
• linux-aarch64, linux-aarch64-musl, macos-aarch64, ios-aarch64, ios-simulator-aarch64, android-aarch64, and windows-aarch64:
• OS_ARCH == "aarch64"
• Formal Silk comparisons also accept the ARM64 aliases "arm64" and "aarch" in any letter case, including through compile-time string constants, even though the canonical OS_ARCH value remains "aarch64".
• wasm32-unknown-unknown and wasm32-wasi:
• OS_ARCH == "wasm32"
• amdgcn-amd-amdhsa-gfx942, amdgcn-amd-amdhsa-gfx1100, and amdgcn-amd-amdhsa-gfx1151:
• OS_ARCH == "amdgcn"

OS_IS_UNIX#

Whether the compilation target is a UNIX family target.

Current compiler target set:

• linux-x86_64: true
• linux-x86_64-musl: true
• linux-aarch64: true
• linux-aarch64-musl: true
• macos-x86_64: true
• macos-aarch64: true
• ios-aarch64: true
• ios-simulator-aarch64: true
• ios-simulator-x86_64: true
• android-aarch64: true
• windows-x86_64: false
• windows-aarch64: false
• wasm32-unknown-unknown: false
• wasm32-wasi: false
• amdgcn-amd-amdhsa-gfx942: false
• amdgcn-amd-amdhsa-gfx1100: false
• amdgcn-amd-amdhsa-gfx1151: false

OS_IS_POSIX#

Whether the compilation target is a POSIX target.

Current compiler target set:

• linux-x86_64: true
• linux-x86_64-musl: true
• linux-aarch64: true
• linux-aarch64-musl: true
• macos-x86_64: true
• macos-aarch64: true
• ios-aarch64: true
• ios-simulator-aarch64: true
• ios-simulator-x86_64: true
• android-aarch64: true
• windows-x86_64: false
• windows-aarch64: false
• wasm32-unknown-unknown: false
• wasm32-wasi: false
• amdgcn-amd-amdhsa-gfx942: false
• amdgcn-amd-amdhsa-gfx1100: false
• amdgcn-amd-amdhsa-gfx1151: false

Relationship to std::os#

The standard library provides std::os helpers that expose the same metadata in a namespaced form and additionally map these strings into enums for use with match (see os; targets not covered by the current enum set map to Unknown).

Examples#

Target-gated behavior#

import std::os;
import { println } from "std/io";

fn main () -> int {
  if OS_IS_POSIX {
    println("posix");
  }

  match (std::os::platform()) {
    std::os::Platform::Linux => println("linux"),
    std::os::Platform::WASI => println("wasi"),
    std::os::Platform::Unknown => println("unknown"),
  };

  return 0;
}

Formal Silk requirements#

#require OS_IS_POSIX;