log.Fatalf("opening sidecar log file for child: %v", err)
		}
		defer childLog.Close()
		cmd.Stderr = childLog
	}

	if reportCrashes {
		pipe, err := cmd.StdinPipe()
		if err != nil {
			log.Fatalf("StdinPipe: %v", err)
		}

		crashmonitor.Parent(pipe.(*os.File)) // (this conversion is safe)
	}

	if err := cmd.Start(); err != nil {
		log.Fatalf("can't start telemetry child process: %v", err)
	}

	//
	// When issue #61080 was present, a long-lived "hang" subprocess would
	// occasionally inherit the fork/exec status pipe from an "exit" subprocess,
	// causing the parent process (which expects to see an EOF on that pipe almost
	// immediately) to unexpectedly block on reading from the pipe.
	var (
		nHangs       = runtime.GOMAXPROCS(0)
		nExits       = runtime.GOMAXPROCS(0)
		hangs, exits sync.WaitGroup
	)

// it doesn't matter.
//sys	fcntl(fd int, cmd int, arg int) (val int, err error)
//sys	Dup2(old int, new int) (err error)

//sysnb pipe(p *[2]_C_int) (err error)

func Pipe(p []int) (err error) {
	if len(p) != 2 {
		return EINVAL
	}
	var pp [2]_C_int
	err = pipe(&pp)
	if err == nil {
		p[0] = int(pp[0])
		p[1] = int(pp[1])
	}
	return
}

		t.Skip("AllThreadsSyscall disabled with cgo")
	}

	rd, wr, err := os.Pipe()
	if err != nil {
		t.Fatalf("unable to obtain a pipe: %v", err)
	}

	// Perform a blocking read on the pipe.
	var wg sync.WaitGroup
	ready := make(chan bool)
	wg.Add(1)
	go func() {
		data := make([]byte, 1)

	t.Helper()
	c1, c2, stop, err := mp()
	if err != nil {
		t.Fatalf("unable to make pipe: %v", err)
	}
	var once sync.Once
	defer once.Do(func() { stop() })
	timer := time.AfterFunc(time.Minute, func() {
		once.Do(func() {
			t.Error("test timed out; terminating pipe")
			stop()
		})
	})
	defer timer.Stop()
	f(t, c1, c2)
}

			{"MZXW", "6YTB"},
			{"MZXW", "6Y", "TB"},
		}, nil},
	}

	for _, testcase := range testcases {
		for _, chunks := range testcase.chunkCombinations {
			pr, pw := io.Pipe()

			// Write the encoded chunks into the pipe
			go func() {
				for _, chunk := range chunks {
					pw.Write([]byte(chunk))
				}
				pw.Close()
			}()

			decoder := NewDecoder(StdEncoding, pr)

		return nil
	}
	readers := make([]*metacacheReader, len(disks))
	defer func() {
		for _, r := range readers {
			r.Close()
		}
	}()
	for i := range disks {
		r, w := io.Pipe()
		// Make sure we close the pipe so blocked writes doesn't stay around.
		defer r.CloseWithError(context.Canceled)

		readers[i] = newMetacacheReader(r)
		d := disks[i]

		// Send request to each disk.
		go func() {

//go:cgo_unsafe_args
func read(fd int32, p unsafe.Pointer, n int32) int32 {
	ret := libcCall(unsafe.Pointer(abi.FuncPCABI0(read_trampoline)), unsafe.Pointer(&fd))
	KeepAlive(p)
	return ret
}
func read_trampoline()

func pipe() (r, w int32, errno int32) {
	var p [2]int32
	errno = libcCall(unsafe.Pointer(abi.FuncPCABI0(pipe_trampoline)), noescape(unsafe.Pointer(&p)))
	return p[0], p[1], errno
}
func pipe_trampoline()

//go:nosplit

	if err != nil {
		return nil, err
	}
	ok, err := clnt.BucketExists(r.Context(), bucket)
	if err != nil {
		return nil, err
	}
	if !ok {
		return nil, os.ErrNotExist
	}

	pr, pw := io.Pipe()

	wa := &writerAt{
		buffer: make(map[int64][]byte),
		w:      pw,
		r:      pr,
		wg:     &sync.WaitGroup{},
	}
	wa.wg.Add(1)
	go func() {

	re(`-m(no-)?ssse3`),
	re(`-mthumb(-interwork)?`),
	re(`-mthreads`),
	re(`-mwindows`),
	re(`-no-canonical-prefixes`),
	re(`--param=ssp-buffer-size=[0-9]*`),
	re(`-pedantic(-errors)?`),
	re(`-pipe`),
	re(`-pthread`),
	re(`-?-std=([^@\-].*)`),
	re(`-?-stdlib=([^@\-].*)`),
	re(`--sysroot=([^@\-].*)`),
	re(`-w`),
	re(`-x([^@\-].*)`),
	re(`-v`),
}

var validCompilerFlagsWithNextArg = []string{