environment variables work in a similar way for C++ code.

# Go references to C

Within the Go file, C's struct field names that are keywords in Go
can be accessed by prefixing them with an underscore: if x points at a C
struct with a field named "type", x._type accesses the field.
C struct fields that cannot be expressed in Go, such as bit fields
or misaligned data, are omitted in the Go struct, replaced by

* [The Go Forum](https://forum.golangbridge.org/), a web-based forum

* [Gophers Slack](https://gophers.slack.com), use the [invite app](https://invite.slack.golangbridge.org/) for access

* [Stack Overflow](https://stackoverflow.com/questions/tagged/go) with questions tagged "go"

depends on functionality of the <i>imported</i> package
(<a href="#Program_initialization_and_execution">§Program initialization and execution</a>)
and enables access to <a href="#Exported_identifiers">exported</a> identifiers
of that package.
The import names an identifier (PackageName) to be used for access and an ImportPath
that specifies the package to be imported.
</p>

<pre class="ebnf">

	defer func() {
		if r := recover(); r != nil {
			t.Fatalf("NewReader panicked: %s", r)
		}
	}()
	// Previously, this would trigger a panic as we attempt to read from
	// an io.SectionReader which would access a slice at a negative offset
	// as the section reader offset & size were < 0.
	NewReader(bytes.NewReader(data), int64(len(data))+1875)

	RET
TEXT ·a8(SB), 0, $0-0
	CMPL runtime·writeBarrier(SB), $0
	ADDQ AX, R15 // ERROR "when dynamic linking, R15 is clobbered by a global variable access and is used here"
	RET
TEXT ·a9(SB), 0, $0-0
	CMPL runtime·writeBarrier(SB), $0
	ORQ R15, R15 // ERROR "when dynamic linking, R15 is clobbered by a global variable access and is used here"
	RET
TEXT ·a10(SB), 0, $0-0

	bodyOffset, err := f.findBodyOffset()
	if err != nil {
		return
	}
	return f.headerOffset + bodyOffset, nil
}

// Open returns a [ReadCloser] that provides access to the [File]'s contents.
// Multiple files may be read concurrently.
func (f *File) Open() (io.ReadCloser, error) {
	bodyOffset, err := f.findBodyOffset()
	if err != nil {
		return nil, err
	}

// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

// Package tar implements access to tar archives.
//
// Tape archives (tar) are a file format for storing a sequence of files that
// can be read and written in a streaming manner.
// This package aims to cover most variations of the format,
// including those produced by GNU and BSD tar tools.

in the Go assembler the names <code>SP</code> and <code>PC</code>
are still treated specially;
for instance, references to <code>SP</code> require a symbol,
much like <code>FP</code>.
To access the actual hardware register use the true <code>R</code> name.
For example, on the ARM architecture the hardware
<code>SP</code> and <code>PC</code> are accessible as
<code>R13</code> and <code>R15</code>.
</p>

<p>

// Arena represents a collection of Go values allocated and freed together.
// Arenas are useful for improving efficiency as they may be freed back to
// the runtime manually, though any memory obtained from freed arenas must
// not be accessed once that happens. An Arena is automatically freed once
// it is no longer referenced, so it must be kept alive (see runtime.KeepAlive)
// until any memory allocated from it is no longer needed.
//

					f.Preamble += "#line 1 \"cgo-generated-wrapper\"\n"
				}
			}

		case *ast.FuncDecl:
			// Also, reject attempts to declare methods on C.T or *C.T.
			// (The generated code would otherwise accept this
			// invalid input; see issue #57926.)
			if decl.Recv != nil && len(decl.Recv.List) > 0 {
				recvType := decl.Recv.List[0].Type
				if recvType != nil {
					t := recvType