groupPool.Put(gs)
	}
	s.prefix.Free()
}

func (s *handleState) openGroups() {
	for _, n := range s.h.groups[s.h.nOpenGroups:] {
		s.openGroup(n)
	}
}

// Separator for group names and keys.
const keyComponentSep = '.'

// openGroup starts a new group of attributes
// with the given name.
func (s *handleState) openGroup(name string) {
	if s.h.json {
		s.appendKey(name)
		s.buf.WriteByte('{')

func lstatNolog(name string) (FileInfo, error) {
	followSurrogates := false
	if name != "" && IsPathSeparator(name[len(name)-1]) {
		// We try to implement POSIX semantics for Lstat path resolution
		// (per https://pubs.opengroup.org/onlinepubs/9699919799.2013edition/basedefs/V1_chap04.html#tag_04_12):
		// symlinks before the last separator in the path must be resolved. Since
		// the last separator in this case follows the last path element, we should

	// Most notably, it cannot support sparse files, files larger than 8GiB,
	// filenames larger than 256 characters, and non-ASCII filenames.
	//
	// Reference:
	//	http://pubs.opengroup.org/onlinepubs/9699919799/utilities/pax.html#tag_20_92_13_06
	FormatUSTAR

	// FormatPAX represents the PAX header format defined in POSIX.1-2001.
	//
	// PAX extends USTAR by writing a special file with Typeflag TypeXHeader

			t.Skipf("skipping %#q: contains a bare newline", b)
		}

		// We use the printf shell command to echo the arguments because, per
		// https://pubs.opengroup.org/onlinepubs/9699919799/utilities/echo.html#tag_20_37_16:
		// “It is not possible to use echo portably across all POSIX systems unless
		// both -n (as the first argument) and escape sequences are omitted.”

func TestFifoEOF(t *testing.T) {
	t.Parallel()

	dir := t.TempDir()
	fifoName := filepath.Join(dir, "fifo")
	if err := syscall.Mkfifo(fifoName, 0600); err != nil {
		t.Fatal(err)
	}

	// Per https://pubs.opengroup.org/onlinepubs/9699919799/functions/open.html#tag_16_357_03:
	//
	// - “If O_NONBLOCK is clear, an open() for reading-only shall block the
	//   calling thread until a thread opens the file for writing. An open() for

	// blocking SIGTTOU signals or the process is ignoring SIGTTOU
	// signals, the process shall be allowed to perform the
	// operation, and no signal is sent."
	//  -https://pubs.opengroup.org/onlinepubs/9699919799/functions/tcsetpgrp.html
	//
	// We are changing the terminal to put us in the foreground, so
	// we must ignore SIGTTOU. We are also an orphaned process

	// The tzdata information can be followed by a string that describes
	// how to handle DST transitions not recorded in zoneTrans.
	// The format is the TZ environment variable without a colon; see
	// https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap08.html.
	// Example string, for America/Los_Angeles: PST8PDT,M3.2.0,M11.1.0
	extend string

	// Most lookups will be for the current time.

// sysStat, if non-nil, populates h from system-dependent fields of fi.
var sysStat func(fi fs.FileInfo, h *Header, doNameLookups bool) error

const (
	// Mode constants from the USTAR spec:
	// See http://pubs.opengroup.org/onlinepubs/9699919799/utilities/pax.html#tag_20_92_13_06
	c_ISUID = 04000 // Set uid
	c_ISGID = 02000 // Set gid
	c_ISVTX = 01000 // Save text (sticky bit)

		t.Fatal(err)
	}

	linklink := filepath.Join(td, "linklink")
	if err := os.Symlink("link", linklink); err != nil {
		t.Fatal(err)
	}

	// Per https://pubs.opengroup.org/onlinepubs/9699919799.2013edition/basedefs/V1_chap04.html#tag_04_12:
	// “A pathname that contains at least one non- <slash> character and that ends
	// with one or more trailing <slash> characters shall not be resolved

	return envList("PKG_CONFIG", cfg.DefaultPkgConfig)[0]
}

// splitPkgConfigOutput parses the pkg-config output into a slice of flags.
// This implements the shell quoting semantics described in
// https://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_02,
// except that it does not support parameter or arithmetic expansion or command
// substitution and hard-codes the <blank> delimiters instead of reading them