When the Go tool sees that one or more Go files use the special import
"C", it will look for other non-Go files in the directory and compile
them as part of the Go package. Any .c, .s, .S or .sx files will be
compiled with the C compiler. Any .cc, .cpp, or .cxx files will be
compiled with the C++ compiler. Any .f, .F, .for or .f90 files will be
compiled with the fortran compiler. Any .h, .hh, .hpp, or .hxx files will

		}
		f.walk(n.Type, ctxType, visit)
		if n.Body != nil {
			f.walk(n.Body, ctxStmt, visit)
		}

	case *ast.File:
		f.walk(n.Decls, ctxDecl, visit)

	case *ast.Package:
		for _, file := range n.Files {
			f.walk(file, ctxFile, visit)
		}

	case []ast.Decl:
		for _, d := range n {
			f.walk(d, context, visit)
		}
	case []ast.Expr:
		for i := range n {
			f.walk(&n[i], context, visit)
		}

pkg go/types, method (*Chan) Dir() ChanDir
pkg go/types, method (*Chan) Elem() Type
pkg go/types, method (*Chan) String() string
pkg go/types, method (*Chan) Underlying() Type
pkg go/types, method (*Checker) Files([]*ast.File) error
pkg go/types, method (*Config) Check(string, *token.FileSet, []*ast.File, *Info) (*Package, error)
pkg go/types, method (*Const) Exported() bool
pkg go/types, method (*Const) Id() string

	TypeXHeader = 'x'

	// Type 'g' is used by the PAX format to store key-value records that
	// are relevant to all subsequent files.
	// This package only supports parsing and composing such headers,
	// but does not currently support persisting the global state across files.
	TypeXGlobalHeader = 'g'

	// Type 'S' indicates a sparse file in the GNU format.
	TypeGNUSparse = 'S'

			content: bytes.Repeat([]byte("abcdefg"), 2048),
			method:  Deflate,
		},
	}

	// write a zip file
	archive := new(bytes.Buffer)
	w := NewWriter(archive)

	for i := range files {
		f := &files[i]
		f.crc32 = crc32.ChecksumIEEE(f.content)
		size := uint64(len(f.content))
		f.uncompressedSize = size
		f.compressedSize = size

		var compressedContent []byte
		if f.method == Deflate {

type readBadSeeker struct{ io.ReadSeeker }

func (rbs *readBadSeeker) Seek(int64, int) (int64, error) { return 0, fmt.Errorf("illegal seek") }

// TestReadTruncation test the ending condition on various truncated files and
// that truncated files are still detected even if the underlying io.Reader
// satisfies io.Seeker.
func TestReadTruncation(t *testing.T) {
	var ss []string
	for _, p := range []string{
		"testdata/gnu.tar",

	files := r.fileList
	i := sort.Search(len(files), func(i int) bool {
		idir, _, _ := split(files[i].name)
		return idir >= dir
	})
	j := sort.Search(len(files), func(j int) bool {
		jdir, _, _ := split(files[j].name)
		return jdir > dir
	})
	return files[i:j]
}

type openDir struct {
	e      *fileListEntry
	files  []fileListEntry
	offset int
}

//
// The table's lower portion shows specialized features of each format,
// such as supported string encodings, support for sub-second timestamps,
// or support for sparse files.
//
// The Writer currently provides no support for sparse files.
type Format int

// Constants to identify various tar formats.
const (
	// Deliberately hide the meaning of constants from public API.

Go 1.20 removed the preinstalled `.a` files for the standard library
from the Go distribution.
Installations now build and cache the standard library like
packages in other modules.
The [`installgoroot` setting](/cmd/go#hdr-Compile_and_install_packages_and_dependencies)
restores the installation and use of preinstalled `.a` files.

There is no plan to remove any of these settings.

### Go 1.19

<pre>
PCALIGN $32
MOVD $2, R0
</pre>
</p>

<h3 id="data-offsets">Interacting with Go types and constants</h3>

<p>
If a package has any .s files, then <code>go build</code> will direct
the compiler to emit a special header called <code>go_asm.h</code>,
which the .s files can then <code>#include</code>.
The file contains symbolic <code>#define</code> constants for the
offsets of Go struct fields, the sizes of Go struct types, and most