forth). A Go function called by C code may take C pointers as arguments,
and it may store non-pointer data, C pointers, or Go pointers to pinned
memory through those pointers. It may not store a Go pointer to unpinned
memory in memory pointed to by a C pointer (which again, implies that it
may not store a string, slice, channel, and so forth). A Go function
called by C code may take a Go pointer but it must preserve the property

pkg runtime, func ReadTrace() []uint8
pkg runtime, func StartTrace() error
pkg runtime, func StopTrace()
pkg runtime, type MemStats struct, GCCPUFraction float64
pkg runtime/trace, func Start(io.Writer) error
pkg runtime/trace, func Stop()
pkg strings, func Compare(string, string) int
pkg strings, func LastIndexByte(string, uint8) int
pkg strings, method (*Reader) Size() int64

func (f *File) saveRef(n *ast.Expr, context astContext) {
	sel := (*n).(*ast.SelectorExpr)
	// For now, assume that the only instance of capital C is when
	// used as the imported package identifier.
	// The parser should take care of scoping in the future, so
	// that we will be able to distinguish a "top-level C" from a
	// local C.
	if l, ok := sel.X.(*ast.Ident); !ok || l.Name != "C" {
		return
	}
	if context == ctxAssign2 {

IdentifierList = identifier { "," identifier } .
ExpressionList = Expression { "," Expression } .
</pre>

<p>
If the type is present, all constants take the type specified, and
the expressions must be <a href="#Assignability">assignable</a> to that type.
If the type is omitted, the constants take the
individual types of the corresponding expressions.
If the expression values are untyped <a href="#Constants">constants</a>,

	// callback(x) calls goCallback(x)
	callbackMutex.Lock()
	callbackToken++
	i := callbackToken
	callbackFuncs[i] = f
	callbackMutex.Unlock()

	// Pass the address of i because the C function was written to
	// take a pointer.  We could pass an int if we felt like
	// rewriting the C code.
	C.callback(unsafe.Pointer(&i))

	callbackMutex.Lock()
	delete(callbackFuncs, i)
	callbackMutex.Unlock()
}

//export goCallback

ExpressionList = Expression { "," Expression } .
</pre>

<p>
If the type is present, all constants take the type specified, and
the expressions must be <a href="#Assignability">assignable</a> to that type,
which must not be a type parameter.
If the type is omitted, the constants take the
individual types of the corresponding expressions.
If the expression values are untyped <a href="#Constants">constants</a>,

// 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.

	}

	// If seconds is negative, then perform correction.
	sign := ""
	if secs < 0 {
		sign = "-"             // Remember sign
		secs = -(secs + 1)     // Add a second to secs
		nsecs = -(nsecs - 1e9) // Take that second away from nsecs
	}
	return strings.TrimRight(fmt.Sprintf("%s%d.%09d", sign, secs, nsecs), "0")
}

// parsePAXRecord parses the input PAX record string into a key-value pair.

				bmbuf = make([]byte, n)
			}
			b.SetBytes(int64(n))
			f(b, n)
		})
	}
}

var indexSizes = []int{10, 32, 4 << 10, 4 << 20, 64 << 20}

var isRaceBuilder = strings.HasSuffix(testenv.Builder(), "-race")

func BenchmarkIndexByte(b *testing.B) {
	benchBytes(b, indexSizes, bmIndexByte(IndexByte))
}

func BenchmarkIndexBytePortable(b *testing.B) {
	benchBytes(b, indexSizes, bmIndexByte(IndexBytePortable))
}