Re: [Boost-users] HOWTO: Connect Boost Signals & Slots to Qt Signals & Slots

Subject: Re: [Boost-users] HOWTO: Connect Boost Signals & Slots to Qt Signals & Slots
From: John Adamson (john_at_[hidden])
Date: 2013-04-24 03:11:56

On 23 April 2013 18:49, Jeff Flinn <Jeffrey.Flinn_at_[hidden]> wrote:

> Hi John,
>
> Please don't top post. I'm rearranging to make this more readable.
>
> On 4/23/2013 11:55 AM, John Adamson wrote:
>
>> Hi Jeff,
>>
>>>
>>> On 23 April 2013 17:48, Jeff Flinn <Jeffrey.Flinn_at_[hidden]
>>> <mailto:Jeffrey.Flinn_at_gmail.**com <Jeffrey.Flinn_at_[hidden]>>> wrote:
>>>
>>>>     On 4/22/2013 4:27 AM, John Adamson wrote:
>>>>
>>>>                    Hello everyone,
>>>>
>>>>                    Please find the first in a series of articles here:
>>>>
>>>>         http://www.oxforddynamics.com/**__articles/connect_qt_and_**
>>>> boost___signals_and_slots.html<http://www.oxforddynamics.com/__articles/connect_qt_and_boost___signals_and_slots.html>
>>>>
>>>>         <http://www.oxforddynamics.**com/articles/connect_qt_and_**
>>>> boost_signals_and_slots.html<http://www.oxforddynamics.com/articles/connect_qt_and_boost_signals_and_slots.html>
>>>> >
>>>>
>>>>                    I hope it will be of use!
>>>>
>>>>         Moderators: is this type of post is acceptable or not?  Please
>>>>         let me
>>>>         know if it isn't and I won't post Boost related HOWTOs here
>>>> again.
>>>>
>>>
>>>     I haven't compiled the examples, but in my Qt4.8.4 implementation at
>>>     52 of qobjectdefs.h I see:
>>>
>>>     #define Q_EMIT
>>>
>>>     So what effect does it have in the below code?
>>>
>>>          lib_ptr_->signal_1.connect( boost::bind( &Ui::Q_EMIT slot1
>>>                                                 , this
>>>                                                 )
>>>                                    );
>>>
>>>
>> I wouldn't recommend that!  Q_EMIT is the alternative macro for the
>>
>
> Recommend what? I'm just asking a question about what effect Q_EMIT has on
> getting the above line of code to compile given that in Qt4.8.4 (if not all
> versions) Q_EMIT /emit is defined to nothing? My understanding is that
> these keywords are just used to 'document' for the human reader that a
> signal/slot is being called.
>
>
>  'emit' keyword.  You need to define QT_NO_KEYWORDS to work with
>> Boost.Signals, but that prevents the use of the 'emit' keyword.
>>
>
> We never use those poorly chosen lower case macro names and always define
> QT_NO_KEYWORDS as a matter of best practices.
>
>
> Jeff
>

Hello again Jeff,

I have not replied here before and did not anticipate my reply would be
'top-posted'.  Thank you for correcting it.

You phrased your question badly (it wasn't clear why you made it look like
you were redefining Q_EMIT) but I see what you meant now.  I don't want
this to descend into a post about Qt only so I'll simply say: yes, you
don't need the Q_EMIT keyword.  To avoid confusion I have also updated the
article.

John