code review 10981043: cmd/cgo: clarify the underscore prefix rule and C union...

cmd/cgo: clarify the underscore prefix rule and C union representation in Go.

[minux1, 2013-07-07 15:55:17]

Hello golang-dev@googlegroups.com,

I'd like you to review this change to
https://code.google.com/p/go/

[rsc, 2013-07-08 19:34:07]

https://codereview.appspot.com/10981043/diff/6001/src/cmd/cgo/doc.go
File src/cmd/cgo/doc.go (right):

https://codereview.appspot.com/10981043/diff/6001/src/cmd/cgo/doc.go#newcode52
src/cmd/cgo/doc.go:52: Within the Go file, C's struct field names that are
keywords in Go
Is it not also true of C identifiers?

[minux1, 2013-07-08 19:51:07]

On Tue, Jul 9, 2013 at 3:34 AM, <rsc@golang.org> wrote:

>
>
https://codereview.appspot.**com/10981043/diff/6001/src/**cmd/cgo/doc.go<http...
> File src/cmd/cgo/doc.go (right):
>
> https://codereview.appspot.**com/10981043/diff/6001/src/**
>
cmd/cgo/doc.go#newcode52<https://codereview.appspot.com/10981043/diff/6001/src/cmd/cgo/doc.go#newcode52>
> src/cmd/cgo/doc.go:52: Within the Go file, C's struct field names that
> are keywords in Go
> Is it not also true of C identifiers?
>
did it used to work?

i tested the following programs, all of them generate a gcc error that
_type doesn't exist.
// a type named "type“
package f

// typedef int type;
import "C"
type T  C._type


// a variable named "type"
package f

// int type;
import "C"

var t = C._type


// a function named "type"
package f

// int type() { return 42; }
import "C"

var t = C._type()


and once i changed type to _type, they can all be built.

[rsc, 2013-07-08 19:58:05]

LGTM

I guess that makes sense: otherwise there'd be an ambiguity.

Russ

[minux1, 2013-07-11 20:34:17]

*** Submitted as https://code.google.com/p/go/source/detail?r=71b65f4dbe6f ***

cmd/cgo: clarify the underscore prefix rule and C union representation in Go.

R=golang-dev, rsc
CC=golang-dev
https://codereview.appspot.com/10981043