// FormatUnknown indicates that the format is unknown.
	FormatUnknown

	// The format of the original Unix V7 tar tool prior to standardization.
	formatV7

	// FormatUSTAR represents the USTAR header format defined in POSIX.1-1988.
	//
	// While this format is compatible with most tar readers,
	// the format has several limitations making it unsuitable for some usages.

				format.mustNotBe(FormatGNU)
			}
			whyNoUSTAR = "USTAR does not support sparse files"
			format.mustNotBe(FormatUSTAR)
		}
	*/

	// Check desired format.
	if wantFormat := h.Format; wantFormat != FormatUnknown {
		if wantFormat.has(FormatPAX) && !preferPAX {
			wantFormat.mayBe(FormatUSTAR) // PAX implies USTAR allowed too
		}
		format.mayOnlyBe(wantFormat) // Set union of formats allowed and format wanted
	}

			if err := tr.handleSparseFile(hdr, rawHdr); err != nil {
				return nil, err
			}

			// Set the final guess at the format.
			if format.has(FormatUSTAR) && format.has(FormatPAX) {
				format.mayOnlyBe(FormatUSTAR)
			}
			hdr.Format = format
			return hdr, nil // This is a file, so stop
		}
	}
}

// handleRegularFile sets up the current file reader and padding such that it

		tw.hdr.AccessTime = time.Time{}
		tw.hdr.ChangeTime = time.Time{}
	}

	allowedFormats, paxHdrs, err := tw.hdr.allowedFormats()
	switch {
	case allowedFormats.has(FormatUSTAR):
		tw.err = tw.writeUSTARHeader(&tw.hdr)
		return tw.err
	case allowedFormats.has(FormatPAX):
		tw.err = tw.writePAXHeader(&tw.hdr, paxHdrs)
		return tw.err
	case allowedFormats.has(FormatGNU):

			PAXRecords: map[string]string{"path": "global1", "mtime": "1500000000.0"},
			Format:     FormatPAX,
		}, {
			Typeflag: TypeReg,
			Name:     "file1",
			ModTime:  time.Unix(0, 0),
			Format:   FormatUSTAR,
		}, {
			Typeflag:   TypeReg,
			Name:       "file2",
			PAXRecords: map[string]string{"path": "file2"},
			ModTime:    time.Unix(0, 0),
			Format:     FormatPAX,
		}, {

pkg archive/tar, const FormatGNU = 8
pkg archive/tar, const FormatGNU Format
pkg archive/tar, const FormatPAX = 4
pkg archive/tar, const FormatPAX Format
pkg archive/tar, const FormatUSTAR = 2
pkg archive/tar, const FormatUSTAR Format
pkg archive/tar, const FormatUnknown = 0
pkg archive/tar, const FormatUnknown Format
pkg archive/tar, method (Format) String() string
pkg archive/tar, type Format int
pkg archive/tar, type Header struct, Format Format

		{"ErrInsecurePath", Var, 20},
		{"ErrWriteAfterClose", Var, 0},
		{"ErrWriteTooLong", Var, 0},
		{"FileInfoHeader", Func, 1},
		{"Format", Type, 10},
		{"FormatGNU", Const, 10},
		{"FormatPAX", Const, 10},
		{"FormatUSTAR", Const, 10},
		{"FormatUnknown", Const, 10},
		{"Header", Type, 0},
		{"Header.AccessTime", Field, 0},
		{"Header.ChangeTime", Field, 0},
		{"Header.Devmajor", Field, 0},
		{"Header.Devminor", Field, 0},