golang.org/x/sys v0.19.0: unix.ClockGettime

Clean-room public code sample — generation instructions

Write a brand-new, minimal, self-contained code sample in this clean-room directory.
Do not copy, paraphrase, or reference any existing project source. Work only from this spec.

A csx.json manifest scaffold already exists. Do not recreate it from memory. Preserve its case.goal, packages and symbols; fill its empty case.contract with exact assertions and correct its environment, commands and verifierAdapter for the files you generate.

Goal: verify golang.org/x/sys/unix.ClockGettime in pkg:golang/golang.org/x/sys@v0.19.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/golang.org/x/sys@v0.19.0
Demonstrate these symbols/APIs:
  - golang.org/x/sys/unix.ClockGettime

Rules:
  - One focused purpose; the smallest project that proves the goal.
  - Include a contract test (test/contract.*) that runs OFFLINE and exits 0 exactly when the goal behavior works.
  - Pin every dependency with a lockfile so resolution is reproducible.
  - No secrets, credentials, or tokens. No real URLs (only example.com or localhost). No absolute paths.
  - No personal names, emails, company names, or project identifiers of any kind.
  - No binaries and no generated output (node_modules, dist, target, venv, .git, .env).
  - Keep it under 200 files and 256KB packed.

{"case":{"caseId":"case:sha256:5c49d15743f64218ec8cd39198065914b6ab5ea34fae03b30f0c4788f07052cb","contract":["unix.ClockGettime with unix.CLOCK_REALTIME succeeds and reports positive Sec and valid Nsec range","unix.ClockGettime with unix.CLOCK_MONOTONIC succeeds and reports non-negative Sec and valid Nsec range","Successive unix.ClockGettime calls with unix.CLOCK_MONOTONIC are monotonically non-decreasing","unix.ClockGettime returns unix.EINVAL for an invalid clock ID"],"goal":"verify golang.org/x/sys/unix.ClockGettime in pkg:golang/golang.org/x/sys@v0.19.0","kind":"HOW","packages":["pkg:golang/golang.org/x/sys@v0.19.0"],"schemaVersion":1,"symbols":["golang.org/x/sys/unix.ClockGettime"]},"contractCommand":["go","run","./test"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"golang","language":"go","libc":"glibc","libcVersion":"2.39","os":"linux","osVersionBucket":"24","packageManager":"go","packageManagerVersion":"1.26.6","runtime":"go","runtimeVersion":"1.26.6","schemaVersion":1},"license":"MIT-0","packages":["pkg:golang/golang.org/x/sys@v0.19.0"],"schemaVersion":1,"subject":"pkg:golang/golang.org/x/sys@v0.19.0","symbols":["golang.org/x/sys/unix.ClockGettime"],"verifierAdapter":"golang@1"}

module example.com/sample

go 1.26.6

require golang.org/x/sys v0.19.0

golang.org/x/sys v0.19.0 h1:q5f1RH2jigJ1MoAWp2KTp3gm5zAGFUTarQZ5U386+4o=
golang.org/x/sys v0.19.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=

package main

import (
	"fmt"
	"os"

	"golang.org/x/sys/unix"
)

func main() {
	var ts unix.Timespec
	if err := unix.ClockGettime(unix.CLOCK_MONOTONIC, &ts); err != nil {
		fmt.Fprintf(os.Stderr, "ClockGettime failed: %v\n", err)
		os.Exit(1)
	}

	fmt.Printf("CLOCK_MONOTONIC time: %d.%09d\n", ts.Sec, ts.Nsec)
}

{
  "schemaVersion": 1,
  "goal": "verify golang.org/x/sys/unix.ClockGettime in pkg:golang/golang.org/x/sys@v0.19.0",
  "kind": "HOW",
  "packages": [
    "pkg:golang/golang.org/x/sys@v0.19.0"
  ],
  "symbols": [
    "golang.org/x/sys/unix.ClockGettime"
  ]
}

package main

import (
	"errors"
	"fmt"
	"os"

	"golang.org/x/sys/unix"
)

func main() {
	if err := runTests(); err != nil {
		fmt.Fprintf(os.Stderr, "Contract test failed: %v\n", err)
		os.Exit(1)
	}
	fmt.Println("All contract assertions passed.")
}

func runTests() error {
	// 1. unix.ClockGettime with unix.CLOCK_REALTIME succeeds and reports positive Sec and valid Nsec range
	var realTs unix.Timespec
	if err := unix.ClockGettime(unix.CLOCK_REALTIME, &realTs); err != nil {
		return fmt.Errorf("unix.ClockGettime failed for CLOCK_REALTIME: %w", err)
	}
	if realTs.Sec <= 0 {
		return fmt.Errorf("expected positive Sec for CLOCK_REALTIME, got %d", realTs.Sec)
	}
	if realTs.Nsec < 0 || realTs.Nsec >= 1_000_000_000 {
		return fmt.Errorf("expected Nsec in [0, 1e9), got %d", realTs.Nsec)
	}

	// 2. unix.ClockGettime with unix.CLOCK_MONOTONIC succeeds and reports non-negative Sec and valid Nsec range
	var monoTs1 unix.Timespec
	if err := unix.ClockGettime(unix.CLOCK_MONOTONIC, &monoTs1); err != nil {
		return fmt.Errorf("unix.ClockGettime failed for CLOCK_MONOTONIC: %w", err)
	}
	if monoTs1.Sec < 0 {
		return fmt.Errorf("expected non-negative Sec for CLOCK_MONOTONIC, got %d", monoTs1.Sec)
	}
	if monoTs1.Nsec < 0 || monoTs1.Nsec >= 1_000_000_000 {
		return fmt.Errorf("expected Nsec in [0, 1e9), got %d", monoTs1.Nsec)
	}

	// 3. Successive unix.ClockGettime calls with unix.CLOCK_MONOTONIC are monotonically non-decreasing
	var monoTs2 unix.Timespec
	if err := unix.ClockGettime(unix.CLOCK_MONOTONIC, &monoTs2); err != nil {
		return fmt.Errorf("unix.ClockGettime second call failed: %w", err)
	}
	if monoTs2.Sec < monoTs1.Sec || (monoTs2.Sec == monoTs1.Sec && monoTs2.Nsec < monoTs1.Nsec) {
		return fmt.Errorf("clock moved backwards: monoTs1=%d.%09d, monoTs2=%d.%09d", monoTs1.Sec, monoTs1.Nsec, monoTs2.Sec, monoTs2.Nsec)
	}

	// 4. unix.ClockGettime returns unix.EINVAL for an invalid clock ID
	var invalidTs unix.Timespec
	err := unix.ClockGettime(-1, &invalidTs)
	if err == nil {
		return fmt.Errorf("expected unix.ClockGettime(-1) to fail, but succeeded")
	}
	if !errors.Is(err, unix.EINVAL) {
		return fmt.Errorf("expected unix.EINVAL for invalid clock ID -1, got %w", err)
	}

	return nil
}