code review 4958053: cgo: explain how to free something

cgo: explain how to free something

[rsc, 2011-08-31 11:04:01]

Hello golang-dev (cc: golang-dev@googlegroups.com),

I'd like you to review this change to
https://go.googlecode.com/hg/

[niemeyer, 2011-08-31 11:18:18]

http://codereview.appspot.com/4958053/diff/1/src/cmd/cgo/doc.go
File src/cmd/cgo/doc.go (right):

http://codereview.appspot.com/4958053/diff/1/src/cmd/cgo/doc.go#newcode75
src/cmd/cgo/doc.go:75: // Go string to C string - caller must free with C.free
This is not strictly true. This function is pretty much always called when the
pointer is going into C land, and in many cases C can borrow the reference,
which means C.free would double-free. If we're hand-holding the developer we
should explain further.

[rsc, 2011-08-31 11:26:57]

I am just trying to point out that C.free exists,
a fact which might not be evident at first glance.
I don't want this to turn into a C tutorial.

Russ

[rsc, 2011-08-31 11:38:29]

Hello golang-dev@googlegroups.com, n13m3y3r@gmail.com (cc:
golang-dev@googlegroups.com),

Please take another look.

[r, 2011-08-31 11:50:54]

LGTM

[niemeyer, 2011-08-31 12:11:19]

> I am just trying to point out that C.free exists,

C.free doesn't actually exist unless stdlib.h is included,
which means it already requires some basic understanding
of cgo that I was assuming. Your explanation looks like
a nice improvement either way, thank you. LGTM

[rsc, 2011-08-31 12:17:06]

*** Submitted as http://code.google.com/p/go/source/detail?r=47d429aad39c ***

cgo: explain how to free something

R=golang-dev, n13m3y3r, r
CC=golang-dev
http://codereview.appspot.com/4958053