golang.org/x/sys v0.10.0: unix.Getpagesize

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.Getpagesize in pkg:golang/golang.org/x/sys@v0.10.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/golang.org/x/sys@v0.10.0
Demonstrate these symbols/APIs:
  - golang.org/x/sys/unix.Getpagesize

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:sha256:8a9fc1ff44daa6b1a4eec2e67755fa6b84578be3354235322384eba5f3c7a5b7","contract":["unix.Getpagesize returns a strictly positive integer representing the system memory page size in bytes","unix.Getpagesize returns a page size that is a power of 2 and at least 4096 bytes on Linux","unix.Getpagesize matches os.Getpagesize and syscall.Getpagesize","unix.Getpagesize output can be used to calculate page-aligned buffer allocations"],"goal":"verify golang.org/x/sys/unix.Getpagesize in pkg:golang/golang.org/x/sys@v0.10.0","kind":"HOW","packages":["pkg:golang/golang.org/x/sys@v0.10.0"],"schemaVersion":1,"symbols":["golang.org/x/sys/unix.Getpagesize"]},"contractCommand":["go","run","./test"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"golang","libc":"glibc","libcVersion":"2.39","os":"linux","osVersionBucket":"24","packageManager":"go","schemaVersion":1},"license":"MIT-0","packages":["pkg:golang/golang.org/x/sys@v0.10.0"],"schemaVersion":1,"subject":"pkg:golang/golang.org/x/sys@v0.10.0","symbols":["golang.org/x/sys/unix.Getpagesize"],"verifierAdapter":"golang@1"}

module sample

go 1.26.6

require golang.org/x/sys v0.10.0

golang.org/x/sys v0.10.0 h1:SqMFp9UcQJZa+pmYuAKjd9xq1f0j5rLcDIk0mj4qAsA=
golang.org/x/sys v0.10.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=

package main

import (
	"fmt"

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

// GetPageSize returns the system memory page size in bytes.
func GetPageSize() int {
	return unix.Getpagesize()
}

func main() {
	pageSize := GetPageSize()
	fmt.Printf("System page size: %d bytes\n", pageSize)
}

{
  "schemaVersion": 1,
  "goal": "verify golang.org/x/sys/unix.Getpagesize in pkg:golang/golang.org/x/sys@v0.10.0",
  "kind": "HOW",
  "packages": [
    "pkg:golang/golang.org/x/sys@v0.10.0"
  ],
  "symbols": [
    "golang.org/x/sys/unix.Getpagesize"
  ]
}

package main

import (
	"fmt"
	"os"
	"syscall"

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

func main() {
	pageSize := unix.Getpagesize()

	if pageSize <= 0 {
		fmt.Fprintf(os.Stderr, "contract violation: Getpagesize returned non-positive value %d\n", pageSize)
		os.Exit(1)
	}

	if (pageSize & (pageSize - 1)) != 0 {
		fmt.Fprintf(os.Stderr, "contract violation: Getpagesize %d is not a power of 2\n", pageSize)
		os.Exit(1)
	}
	if pageSize < 4096 {
		fmt.Fprintf(os.Stderr, "contract violation: Getpagesize %d is less than 4096 on Linux\n", pageSize)
		os.Exit(1)
	}

	osSize := os.Getpagesize()
	if pageSize != osSize {
		fmt.Fprintf(os.Stderr, "contract violation: unix.Getpagesize() (%d) != os.Getpagesize() (%d)\n", pageSize, osSize)
		os.Exit(1)
	}
	syscallSize := syscall.Getpagesize()
	if pageSize != syscallSize {
		fmt.Fprintf(os.Stderr, "contract violation: unix.Getpagesize() (%d) != syscall.Getpagesize() (%d)\n", pageSize, syscallSize)
		os.Exit(1)
	}

	numPages := 4
	totalBytes := numPages * pageSize
	buf := make([]byte, totalBytes)
	if len(buf) != totalBytes {
		fmt.Fprintf(os.Stderr, "contract violation: buffer length %d != expected %d\n", len(buf), totalBytes)
		os.Exit(1)
	}
	if len(buf)%pageSize != 0 {
		fmt.Fprintf(os.Stderr, "contract violation: buffer length %d is not a multiple of page size %d\n", len(buf), pageSize)
		os.Exit(1)
	}

	fmt.Printf("contract passed: unix.Getpagesize() returned %d bytes\n", pageSize)
}