[Mesa-dev] [PATCH 7/9] glsl: Make foreach macros usable from C by adding struct keyword.

[Ian Romanick]

On 06/10/2014 12:06 PM, Matt Turner wrote:
> On Tue, Jun 10, 2014 at 11:38 AM, Ian Romanick <idr at freedesktop.org> wrote:
>> On 06/10/2014 11:00 AM, Matt Turner wrote:
>>> ---
>>>  src/glsl/list.h | 22 +++++++++++-----------
>>>  1 file changed, 11 insertions(+), 11 deletions(-)
>>>
>>> diff --git a/src/glsl/list.h b/src/glsl/list.h
>>> index da81062..803aab5 100644
>>> --- a/src/glsl/list.h
>>> +++ b/src/glsl/list.h
>>> @@ -556,13 +556,13 @@ inline void exec_node::insert_before(exec_list *before)
>>>  /**
>>>   * This version is safe even if the current node is removed.
>>>   */
>>> -#define foreach_list_safe(__node, __list)                         \
>>> -   for (exec_node * __node = (__list)->head, * __next = __node->next \
>>> -     ; __next != NULL                                             \
>>> +#define foreach_list_safe(__node, __list)                                    \
>>> +   for (struct exec_node * __node = (__list)->head, * __next = __node->next  \
>>> +     ; __next != NULL                                                        \
>>>       ; __node = __next, __next = __next->next)
>>
>> Did you notice if this adds any warnings in C++ uses?  I seem to recall
>> the compiler squaking if you mixed uses with and without struct.  Or
>> maybe that was just if you mixed struct and class...
> 
> Yep, no new warnings.
> 
> I tried a little test program
> % cat t.cpp
> class asdf {
>     int x;
> };
> 
> void f() {
>     asdf a;
>     struct asdf b;
>     class asdf c;
> }
> 
> and I can't make it generate warnings (other than unused variables)
> regardless of whether I define asdf as a class or a struct.

I did a little more research.  Looking at the commit history, it must
just be an MSVC thing:

commit 78d3cfb5b4fe1dbe052f87458e62cc2be2ecf171
Author: Brian Paul <brianp at vmware.com>
Date:   Sun Nov 4 16:43:44 2012 -0700

    glsl: remove incorrect 'struct' keyword

    ir_variable is a class, not a struct.  Fixes an MSVC warning.

    Reviewed-by: Jose Fonseca <jfonseca at vmware.com>

So, I think it is just class vs struct (and not struct vs nothing) that
causes the warning.