[Development] Qt 6 buildsystem support requirements

[Joerg Bornemann]

On 08/02/2018 10:05 AM, BogDan Vatra via Development wrote:

>>> Well, if we want to have first class Qt on Android support, this feature
>>> is a
>   must. Now, if we can use it also for other platforms that's a
>>> bonus.
>>
>> Which feature exactly? Creating binaries for multiple targets in on compile
>> run? Or also only calling rcc once?
>   
>> The first one I can see, the second one would be just an optimisation when
>> creating multiple binaries.
>   
> First one.

We're now talking about three different things.


1. Build multiple configurations in one go

E.g. I want to build my project on Linux for Linux x86_64 and 
cross-compile at the same time with MinGW. The project knows nothing 
about this.

This is supported by qbs. [1]


2. Build for multiple platforms in one go

E.g. I want to cross-compile Qt with MinGW  on Linux. Host tools (moc, 
rcc, qlalr, qwhatnot) which are built for Linux x86_64. Libs are 
cross-build for Windows in both, release and debug versions.
The project knows about host tools and "multiplexing".

Other famous use cases are: building for Android and iOS.

This is supported by qbs. [2]


3. Build something via 1 or 2 and share equal generated artifacts

We're calling rcc once, because we somehow know that the output will be 
the same for all variants of the build products.

This is not supported by qbs at the moment. [3]


Cheers,

Joerg


[1] http://doc.qt.io/qbs/building-applications.html
[2] http://doc.qt.io/qbs/multiplexing.html
[3] 
https://memegenerator.net/img/instances/61770863/im-sorry-do-u-still-love-me-.jpg