[Development] Notes on "Qt Build Systems" @ QtCon 2016

[Konstantin Tokarev]

06.09.2016, 18:24, "Jake Petroules" <jake.petroules at qt.io>:
>> On Sep 6, 2016, at 5:14 PM, Kevin Kofler <kevin.kofler at chello.at> wrote:
>>
>> Ch'Gans wrote:
>>> I never wanted to use CMake b/c for me it look like a gross hack
>>> (Reminds me of GNU M4).
>>
>> The CMake language is much easier to use than m4, and also there is just one
>> layer rather than having autoconf on top of m4, with shell script snippets
>> mixed in.
>>
>> There is a reason CMake is being proposed for Qt and autotools is not.
>>
>>> Makefiles are out-dated (no punt intended) and so is CMake and any
>>> other Makefile-based tools.
>>> Makefiles are dead! CMake is ill! (Friendly, easy and provocative
>>> argument)
>>
>> CMake can generate other build files than makefiles (e.g., the Ninja
>> generator is basically a drop-in replacement).
>
> Again, Ninja has its architectural limitations as well, so this would not be useful. The problem isn't (just) Makefiles, it's the fact that we don't have a build tool that is fundamentally better and more powerful than anything we've ever had before, and we CAN have this. It's like C++ vs Motorola 68k assembler.

Architecture of ninja is not the biggest problem here - I'd rather argue that if your build graph is unknown ahead of time your build process is flawed. Problem is that CMake often makes it hard to do things which can be easily expressed in terms of make or ninja, e.g. it does not have a concept of build rule (instead you have for write foreach cycles), or such trivial thing as building PCH for gcc turns into the page of ugly cmake code [1]

[1] https://gist.github.com/larsch/573926

>
>> I guess somebody could even get CMake to write Qbs files, it would just be
>> one more generator. :-)
>
> Again, useless, because Qbs is more powerful and at a much higher level of abstraction, so a generator would only be useful in the reverse direction. It's like trying to make a compiler to transform Motorola 68k assembler to C++. Only the reverse transformation of that can done in a useful manner.
>
>>        Kevin Kofler
>>
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>
> --
> Jake Petroules - jake.petroules at qt.io
> Consulting Services Engineer - The Qt Company
> Qbs build tool evangelist - qbs.io
> ,
>
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-- 
Regards,
Konstantin