comment, called the preamble, is used as a header when compiling
the C parts of the package. For example:

	// #include <stdio.h>
	// #include <errno.h>
	import "C"

The preamble may contain any C code, including function and variable
declarations and definitions. These may then be referred to from Go
code as though they were defined in the package "C". All names

SwitchStmt = ExprSwitchStmt | TypeSwitchStmt .
</pre>

<p>
There are two forms: expression switches and type switches.
In an expression switch, the cases contain expressions that are compared
against the value of the switch expression.
In a type switch, the cases contain types that are compared against the
type of a specially annotated switch expression.
The switch expression is evaluated exactly once in a switch statement.
</p>

	paxGNUSparseSize      = "GNU.sparse.size"
	paxGNUSparseRealSize  = "GNU.sparse.realsize"
)

// basicKeys is a set of the PAX keys for which we have built-in support.
// This does not contain "charset" or "comment", which are both PAX-specific,
// so adding them as first-class features of Header is unlikely.
// Users can use the PAXRecords field to set it themselves.
var basicKeys = map[string]bool{

// forces us to be a more liberal.
// Thus, we only reject all keys with NUL, and only reject NULs in values
// for the PAX version of the USTAR string fields.
// The key must not contain an '=' character.
func validPAXRecord(k, v string) bool {
	if k == "" || strings.Contains(k, "=") {
		return false
	}
	switch k {
	case paxPath, paxLinkpath, paxUname, paxGname:
		return !hasNUL(v)

	return sb.String(), needsUnsafe
}

// needsPointerCheck reports whether the type t needs a pointer check.
// This is true if t is a pointer and if the value to which it points
// might contain a pointer.
func (p *Package) needsPointerCheck(f *File, t ast.Expr, arg ast.Expr) bool {
	// An untyped nil does not need a pointer check, and when
	// _cgoCheckPointer returns the untyped nil the type assertion we

pkg syscall (darwin-arm64), type Log2phys_t struct, Devoffset int64
pkg syscall (darwin-arm64), type Log2phys_t struct, Flags uint32
pkg syscall (darwin-arm64), type Msghdr struct
pkg syscall (darwin-arm64), type Msghdr struct, Control *uint8
pkg syscall (darwin-arm64), type Msghdr struct, Controllen uint32
pkg syscall (darwin-arm64), type Msghdr struct, Flags int32
pkg syscall (darwin-arm64), type Msghdr struct, Iov *Iovec

pkg syscall (freebsd-arm64), type Kevent_t struct, Ident uint64
pkg syscall (freebsd-arm64), type Kevent_t struct, Udata *uint8
pkg syscall (freebsd-arm64), type Msghdr struct
pkg syscall (freebsd-arm64), type Msghdr struct, Control *uint8
pkg syscall (freebsd-arm64), type Msghdr struct, Controllen uint32
pkg syscall (freebsd-arm64), type Msghdr struct, Flags int32
pkg syscall (freebsd-arm64), type Msghdr struct, Iov *Iovec

	0x0043 00067 (x.go:3)	PCDATA	$0, $-1
	0x0043 00067 (x.go:3)	CALL	runtime.morestack_noctxt(SB)
	0x0048 00072 (x.go:3)	JMP	0
...
</pre>

<p>
The <code>FUNCDATA</code> and <code>PCDATA</code> directives contain information
for use by the garbage collector; they are introduced by the compiler.
</p>

<p>
To see what gets put in the binary after linking, use <code>go tool objdump</code>:
</p>

<pre>

See the [ZIP specification] for details.

This package does not support disk spanning.

A note about ZIP64:

To be backwards compatible the FileHeader has both 32 and 64 bit Size
fields. The 64 bit fields will always contain the correct value and
for normal archives both fields will be the same. For files requiring
the ZIP64 format the 32 bit fields will be 0xffffffff and the 64 bit
fields must be used instead.

This behavior is controlled by the `winreadlinkvolume` setting.
For Go 1.23, it defaults to `winreadlinkvolume=1`.
Previous versions default to `winreadlinkvolume=0`.

### Go 1.22

Go 1.22 adds a configurable limit to control the maximum acceptable RSA key size
that can be used in TLS handshakes, controlled by the [`tlsmaxrsasize` setting](/pkg/crypto/tls#Conn.Handshake).
The default is tlsmaxrsasize=8192, limiting RSA to 8192-bit keys. To avoid