code review 5154042: cgo: allow Window's specific path characters in flag di...

cgo: allow Window's specific path characters in flag directives.

Example: #cgo windows LDFLAGS: -LC:\\WINDOWS\\system32

[Joe Poirier, 2011-09-29 03:25:29]

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

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

[rsc, 2011-09-29 12:51:18]

Why the doubled backslashes in the example?

Russ

[peterGo, 2011-09-29 14:11:19]

Russ,

The revised safeBytes,

var safeBytes =
[]byte("+-.,/0123456789:=ABCDEFGHIJKLMNOPQRSTUVWXYZ\\_abcdefghijklmnopqrstuvwxyz")

is an interpreted string literal, not a raw string literal. Without the doubled
backslashes, it will fail with an "unknown escape sequence" error.

I would have used a raw string literal.

Peter

On 2011/09/29 12:51:18, rsc wrote:
> Why the doubled backslashes in the example?
> 
> Russ

[rsc, 2011-09-29 15:30:30]

Okay, but why the doubled backslash in

Example: #cgo windows LDFLAGS: -LC:\\WINDOWS\\system32

[Joe Poirier, 2011-09-29 15:50:09]

On Thu, Sep 29, 2011 at 10:30 AM, Russ Cox <rsc@golang.org> wrote:
> Okay, but why the doubled backslash in
> Example: #cgo windows LDFLAGS: -LC:\\WINDOWS\\system32
>

splitQuoted consumes the first backslash.

-joe

[Joe Poirier, 2011-09-29 16:07:58]

On Thu, Sep 29, 2011 at 10:49 AM, Joseph Poirier <jdpoirier@gmail.com> wrote:
> On Thu, Sep 29, 2011 at 10:30 AM, Russ Cox <rsc@golang.org> wrote:
>> Okay, but why the doubled backslash in
>> Example: #cgo windows LDFLAGS: -LC:\\WINDOWS\\system32
>>
>
> splitQuoted consumes the first backslash.
>

splitQuoted correctly views the first backslash as an
escape character and passes on the character being
escaped, which is another backslash in my example.

I believe having to escape backslashes in path strings
is common when developing on Windows but maybe
the real Windows developers can weigh in.

-joe

[brainman, 2011-10-03 01:31:57]

The change LGTM. I would use `` as peterGo suggested and would have / and \ next
to each other.

On 2011/09/29 15:30:30, rsc wrote:
> Okay, but why the doubled backslash in
> 
> Example: #cgo windows LDFLAGS: -LC:\\WINDOWS\\system32

It is our program. We make the rules. At this moment, according to splitQuoted
doco, backslash is used for escaping. Therefore we must use \\ to escape \. If
you want to change this rule and disallow escaping, then we won't have to double
backslash.

Alex

[Joe Poirier, 2011-10-03 16:19:11]

Hello alex.brainman@gmail.com, go.peter.90@gmail.com,
golang-dev@googlegroups.com, rsc@golang.org (cc: golang-dev@googlegroups.com),

Please take another look.

[Joe Poirier, 2011-10-03 16:23:06]

Uses a raw string literal. 

The order is the same since it's consistent with the rest of the characters in
safeBytes, lowest to highest value.

-joe

[brainman, 2011-10-04 04:07:11]

On 2011/10/03 16:23:06, Joe Poirier wrote:
> 
> The order is the same since it's consistent with the rest of the characters in
> safeBytes, lowest to highest value.
> 

You are right. LGTM

[brainman, 2011-10-04 04:07:42]

*** Submitted as http://code.google.com/p/go/source/detail?r=6aa111bd2d11 ***

cgo: allow Window's specific path characters in flag directives.

Example: #cgo windows LDFLAGS: -LC:\\WINDOWS\\system32

R=alex.brainman, go.peter.90, golang-dev, rsc
CC=golang-dev
http://codereview.appspot.com/5154042

Committer: Alex Brainman <alex.brainman@gmail.com>