QtWebEngine and Mingw

[Lubomir I. Ivanov]

On 24 June 2017 at 18:15, Dirk Hohndel <dirk at hohndel.org> wrote:
>
>> On Jun 24, 2017, at 6:59 AM, Lubomir I. Ivanov <neolit123 at gmail.com> wrote:
>>
>> i've just updated my Qt to 5.9.0 on Windows with the Mingw 5.3.0 toolchain.
>>
>> but i'm facing a bug where the WebEngine libaries and cmake files are missing:
>> https://bugreports.qt.io/browse/QTBUG-61394
>>
>> after reading more into it, it seems it might not be an actual bug...:
>> https://bugreports.qt.io/browse/QTBUG-42725
>>
>> people in the above thread say that QWebEngine relies on the Chromium
>> engine as a backend and Chromium cannot be build using Mingw on
>> Windows - MSVC or clang needs to be used, so to me this means that if
>> you want to deploy a Qt based app on Windows that uses QWebEngine it
>> has to be built using MSVC or clang.
>
> Hmm, that's odd. Have you looked at what MXE does about that? Because
> that's what I use to cross build everything. I haven't upgraded that to Qt 5.9,
> though (and I always need to compile that from source anyway)
>

found this error report about MXE and QtWebEngine:
https://github.com/mxe/mxe/issues/1509

"Qt WebEngine on Windows requires MSVC 2013 or MSVC 2015.
QtWebEngine will not be built."

>> if so, that's a bummer.
>
> I would agree. Changing my build environment to clang would not make me
> happy.
>
>> the thread is old, but there are recent comments bellow that suggest
>> to use a fork of QtWebKit, which is what we are using now - is that
>> correct?
>
> We use the "current" (but unmaintained) QtWebKit that is part of the
> sources. Once 5.9.1 is out (which should happen within a week) I will
> build that from source on MXE.

i've downloaded the qtwebkit-5.212.0_alpha2-qt59-mingw530-x86.zip
from here:
https://github.com/annulen/webkit/releases

>
>> i will investigate further into this, but i'm going to assume that
>> switching to clang is a possibility (if QtWebEngine supports that - i
>> don't exactly understand the details here), while MSVC is out of the
>> question?
>
> MSVC is out of the question. clang is possible, but not something I
> look forward to - unless MXE has a clang branch which I haven't seen
> (and yes, I did look).
>

maybe if everything is mingw based and only QtWebEngine is build with
clang and that library is compatible with the rest of the Qt's Mingw
binaries it will work.
but to my understanding the C++ ABI is not compatible between clang
and mingw, which means the above is not possible without
"modifications".

also Qt don't support official llvm or clang binaries on windows and
it's either mingw or MSVC unless one attempts to build the whole Qt
himself with a different compiler.

lubomir
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