that can be converted to type <code>T</code>.
</p>

<pre class="ebnf">
Conversion = Type "(" Expression [ "," ] ")" .
</pre>

<p>
If the type starts with the operator <code>*</code> or <code>&lt;-</code>,
or if the type starts with the keyword <code>func</code>
and has no result list, it must be parenthesized when
necessary to avoid ambiguity:
</p>

<pre>

as C.stdout, or functions such as C.putchar.

If the import of "C" is immediately preceded by a comment, that
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

The [SliceAt(typ Type, p unsafe.Pointer, len int)] function
returns a Value representing a slice whose underlying array starts

Even so, Go provides a mechanism called GODEBUG to
reduce the impact such changes have on Go developers
using newer toolchains to compile old code.

A GODEBUG setting is a `key=value` pair
that controls the execution of certain parts of a Go program.
The environment variable `GODEBUG`
can hold a comma-separated list of these settings.
For example, if a Go program is running in an environment that contains

	GODEBUG=http2client=0,http2server=0

	if len(p) == 0 {
		return
	}
	skipParts := sort.Search(len(r.buf), func(i int) bool {
		part := &r.buf[i]
		return part.off+part.n > off
	})
	parts := r.buf[skipParts:]
	if len(parts) > 0 {
		skipBytes := off - parts[0].off
		for _, part := range parts {
			repeat := int(min(part.n-skipBytes, int64(len(p)-n)))
			memset(p[n:n+repeat], part.b)
			n += repeat
			if n == len(p) {
				return
			}

type float64 float64

// complex64 is the set of all complex numbers with float32 real and
// imaginary parts.
type complex64 complex64

// complex128 is the set of all complex numbers with float64 real and
// imaginary parts.
type complex128 complex128

// string is the set of all strings of 8-bit bytes, conventionally but not

that can be converted to type <code>T</code>.
</p>

<pre class="ebnf">
Conversion = Type "(" Expression [ "," ] ")" .
</pre>

<p>
If the type starts with the operator <code>*</code> or <code>&lt;-</code>,
or if the type starts with the keyword <code>func</code>
and has no result list, it must be parenthesized when
necessary to avoid ambiguity:
</p>

<pre>

		c := s[stop-1]
		if c >= utf8.RuneSelf {
			return TrimFunc(s[start:stop], unicode.IsSpace)
		}
		if asciiSpace[c] == 0 {
			break
		}
	}

	// At this point s[start:stop] starts and ends with an ASCII
	// non-space bytes, so we're done. Non-ASCII cases have already
	// been handled above.
	if start == stop {
		// Special case to preserve previous TrimLeftFunc behavior,

			p.errorf(err.Error())
		}
	default:
		p.errorf("register extension not supported on this architecture")
	}
}

// qualifySymbol returns name as a package-qualified symbol name. If
// name starts with a period, qualifySymbol prepends the package
// prefix. Otherwise it returns name unchanged.
func (p *Parser) qualifySymbol(name string) string {
	if strings.HasPrefix(name, ".") {
		name = p.pkgPrefix + name
	}

the start of the function <code>main.main</code>.
</p>

<h3 id="go">Goroutine creation</h3>

<p class="rule">
The <code>go</code> statement that starts a new goroutine
is synchronized before the start of the goroutine's execution.
</p>

<p>
For example, in this program:
</p>

<pre>
var a string

func f() {
	print(a)
}