golang.org/x/sys v0.24.0: unix.BytePtrFromString

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.BytePtrFromString in pkg:golang/golang.org/x/sys@v0.24.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/golang.org/x/sys@v0.24.0
Demonstrate these symbols/APIs:
  - golang.org/x/sys/unix.BytePtrFromString

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:f8e8c8cdf8a0073c9731ca81a4a74c51d9d97dbbabf7664e99c3c9fc5083b023","contract":["unix.BytePtrFromString(\"hello-unix\") returns a non-nil *byte pointing to the string's bytes followed by a trailing NUL (0x00) byte, and nil error","unix.BytePtrFromString(\"\") returns a non-nil *byte whose dereferenced byte is 0x00, and nil error","unix.BytePtrFromString(\"bad\\x00string\") returns a nil *byte and unix.EINVAL when the input string contains an embedded NUL byte"],"goal":"verify golang.org/x/sys/unix.BytePtrFromString in pkg:golang/golang.org/x/sys@v0.24.0","kind":"HOW","packages":["pkg:golang/golang.org/x/sys@v0.24.0"],"schemaVersion":1,"symbols":["golang.org/x/sys/unix.BytePtrFromString"]},"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@v0.24.0"],"schemaVersion":1,"subject":"pkg:golang/golang.org/x/sys@v0.24.0","symbols":["golang.org/x/sys/unix.BytePtrFromString"],"verifierAdapter":"golang@1"}

module example.com/sample

go 1.22

require golang.org/x/sys v0.24.0

golang.org/x/sys v0.24.0 h1:Twjiwq9dn6R1fQcyiK+wQyHWfaz/BJB+YIpzU/Cv3Xg=
golang.org/x/sys v0.24.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=

{
  "schemaVersion": 1,
  "goal": "verify golang.org/x/sys/unix.BytePtrFromString in pkg:golang/golang.org/x/sys@v0.24.0",
  "kind": "HOW",
  "packages": [
    "pkg:golang/golang.org/x/sys@v0.24.0"
  ],
  "symbols": [
    "golang.org/x/sys/unix.BytePtrFromString"
  ]
}

package main

import (
	"errors"
	"os"
	"unsafe"

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

func main() {
	// 1. Valid string returns a pointer to a NUL-terminated byte array.
	input := "hello-unix"
	ptr, err := unix.BytePtrFromString(input)
	if err != nil {
		os.Exit(1)
	}
	if ptr == nil {
		os.Exit(2)
	}
	raw := unsafe.Slice(ptr, len(input)+1)
	if string(raw[:len(input)]) != input {
		os.Exit(3)
	}
	if raw[len(input)] != 0 {
		os.Exit(4)
	}
	if unix.BytePtrToString(ptr) != input {
		os.Exit(5)
	}

	// 2. Empty string returns a valid pointer whose first byte is NUL (0).
	emptyPtr, err := unix.BytePtrFromString("")
	if err != nil || emptyPtr == nil || *emptyPtr != 0 {
		os.Exit(6)
	}

	// 3. String with embedded NUL byte returns nil pointer and unix.EINVAL.
	badPtr, err := unix.BytePtrFromString("bad\x00string")
	if badPtr != nil {
		os.Exit(7)
	}
	if !errors.Is(err, unix.EINVAL) {
		os.Exit(8)
	}
}