func (in *Input) expectText(args ...interface{}) {
	in.Error(append(args, "; got", strconv.Quote(in.Stack.Text()))...)
}

// enabled reports whether the input is enabled by an ifdef, or is at the top level.
func (in *Input) enabled() bool {
	return len(in.ifdefStack) == 0 || in.ifdefStack[len(in.ifdefStack)-1]
}

func (in *Input) expectNewline(directive string) {
	tok := in.Stack.Next()
	if tok != '\n' {

		output = output[1:]
	}

	// Checked printing.
	// Now check machine code layout.

	top := pList.Firstpc
	var text *obj.LSym
	ok = true
	ctxt.DiagFunc = func(format string, args ...interface{}) {
		t.Errorf(format, args...)
		ok = false
	}
	obj.Flushplist(ctxt, pList, nil)

	for p := top; p != nil; p = p.Link {
		if p.As == obj.ATEXT {
			text = p.From.Sym
		}
		hexes := hexByLine[p.Line()]

	// 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 {
		context = ctxExpr
	}
	if context == ctxEmbedType {

generated by cgo. A typical preamble #includes necessary definitions:

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

For more details about the usage of cgo, see the documentation
comment at the top of this file.

Understanding C

Cgo scans the Go source files that import "C" for uses of that
package, such as C.puts. It collects all such identifiers. The next