[webkit-dev] Does someone know how to fix WTF::Function on Windows

[Darin Adler]

Right, that’s what I am looking to undo.

— Darin

Sent from my iPhone

> On Jul 15, 2017, at 12:28 PM, Chris Dumez <cdumez at apple.com> wrote:
> 
> I seem to remember I fixed it last time by calling the WTF::Function constructor explicitly.
> 
> Chris Dumez
> 
>> On Jul 15, 2017, at 9:14 AM, Yusuke SUZUKI <utatane.tea at gmail.com> wrote:
>> 
>> I'm not 100% confident, but can you try it `&testFunction` instead?
>> 
>> Regards,
>> Yusuke Suzuki
>> 
>>> On Sun, Jul 16, 2017 at 1:13 AM, Darin Adler <darin at apple.com> wrote:
>>> Hi folks.
>>> 
>>> On Windows, WTF::Function doesn’t quite work right. Code that is something like this:
>>> 
>>>     void addCallback(WTF::Function<void()>&&);
>>> 
>>>     void testFunction()
>>>     {
>>>         // ...
>>>     }
>>> 
>>>     void addTestFunction()
>>>     {
>>>         addCallback(testFunction);
>>>     }
>>> 
>>> Leads to errors like this:
>>> 
>>>     error C2664: 'void addCallback(WTF::Function<void (void)> &&)': cannot convert argument 1 from 'void (__cdecl *)(void)' to 'WTF::Function<void (void)> &&'
>>>     note: You cannot bind an lvalue to an rvalue reference
>>> 
>>> The problem might have something to do with cdecl vs. stdcall functions, but I am not sure that is the problem. It could be some other problem with how WTF::Function is written. Or it might even be a bug in the Visual Studio compiler. Since I don’t have a Windows machine myself, I was trying to use EWS to figure this out but that was slow. Then I tried using http://webcompiler.cloudapp.net but I could not reproduce any error there when I pasted in cut down code; it just compiled fine.
>>> 
>>> Is there someone who knows how to fix this?
>>> 
>>> Another way to put this is: We want to take off the explicit WTF::Function conversions in functions like canUseWithReason in SimpleLineLayout.cpp, Page::Page in Page.cpp, and Worker::Worker in Worker.cpp and have it still compile and work on Windows. Other platforms seem to compile fine without the explicit WTF::Function.
>>> 
>>> — Darin
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>> 
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