Re: [boost] CMake and Boost Build tests

Subject: Re: [boost] CMake and Boost Build tests
From: Florent Castelli (florent.castelli_at_[hidden])
Date: 2017-07-27 12:12:43

On 27/07/2017 10:24, Edward Diener via Boost wrote:
> On 7/27/2017 1:12 AM, Robert Ramey via Boost wrote:
>> On 7/26/17 7:28 PM, Edward Diener via Boost wrote:
>>
>>> But the case I brought up is that there is no "build' of the 
>>> library, since it is header only, but the library needs to execute 
>>> its tests using CMake. That appears to me to be different from your 
>>> case.
>>
>> Well, there is the safe numerics library which has CMake tests and is 
>> header only.  It's much simpler than the serialization library.
>>
>> https://github.com/robertramey/safe_numerics
>>
>> You'll find a few CMakeLists.txt files in different places like 
>> include/example/test etc.  Not that much unlike bjam where one has 
>> jam files in test, example, etc.
>>
>>>
>>> So you are saying that even when their is no actual library to be 
>>> built, as is the case with a header only library, you still specify 
>>> a CMakeLists.txt file as if you were building a library ?
>>
>> yep - just like for bjam you specify a jam file in the test 
>> directory, for CMake you specifiy a CMakeLists.txt file in the test 
>> directory.
>
> Great, thanks !
>
>>
>>
>>>> This is a serious short coming of CMake.  Given this it's a mystery 
>>>> that CMake has been successful.  But then then look at all the 
>>>> competition it's ever worse!!!  To addressed this, I wrote a walk 
>>>> through in the boost library inclubator to help library developers 
>>>> get started with CMake.  It uses on the safe numerics library CMake 
>>>> as an example.  This example/narrative addresses only header-only 
>>>> files.
>>>
>>> Would you please give a URL ?
>>
>> https://github.com/robertramey/safe_numerics
>>
>> I'm really disappointed you couldn't find this.  It recently was 
>> reviewed for inclusion in boost and accepted!
>
> You said you wrote a walk through in the boost library incubator and I 
> asked for the URL of the walk through. You gave me a link to your safe 
> numerics library on github. I have found 
> http://blincubator.com/tools_cmak/. I will read this.
>
>>
>>> Do you know if CMake has a way of setting usage requirements for all 
>>> builds in a directory ? That is the effect of the project rule in 
>>> Boost Build when running tests. It is very useful and means that you 
>>> do not have to repeat a bunch of usage requirements for each and 
>>> every test.
>>
>> Right.  Every build system has to address this problem.
>>
>> In bjam I can make a "rule" which passes "usage requirements".
>
> You do not have to make a rule since the builtin "project" rule 
> already does this for you.
>
>>
>> In CMake I make a "function" which passes arguments.
>
> So CMake has no way built-in command to say "here are the usage 
> requirements for every target in this directory" other than to have to 
> write a "function" each time ? That seems a bit poor.

It does has some support for things like that, but it scales poorly. 
What you can do instead is have a target with all the requirements you 
want and link against it and they will bubble up.
Or you just use a function, which is not a bad thing, they can remove a 
lot of boilerplate and make the intent clearer.
Would you write ASM all the time? No, you write high level C++. A build 
system is no different.

>
>
>>
>> Similar but different.  For some reason every build system designer 
>> seems to fancy himself a language designer and what we get is some 
>> oddball/irregular "language" for describing the "build".  When it 
>> barely works the release and then start patching it up to so it can 
>> be made to work.  The result is what we have to today.  An assortment 
>> of build languages none of which are very good.  This is addressed by 
>> inventing a NEW build language which isn't really any better than the 
>> one it's meant to replace.  This happens again and again - this is 
>> how we came to be where we are today.
>>
>>> I will look at your serialization CMake code and I assume the other 
>>> working example is for your Safe Numerics library, so I will look at 
>>> that also. Thanks !
>>
>> There are other examples already in boost - made by people who know 
>> more about CMake than I do.  (I hate wasting time on this kind of 
>> stuff). Unfortunately, many of these examples seem to be more 
>> elaborate than necessary and end up totally obscuring that which 
>> starts out simple. Its a chronic programmer disease to start with 
>> something understandable which works and then try to make it perfect 
>> there by mucking it up. Hollywood plastic surgeries have the exact 
>> same problem.
>>
>>>> I've got a lot to say about this and I will be giving a 
>>>> presentation on the subject at CPPCon 2017 for anyone who might be 
>>>> interested. That is the both of you.
>>>
>>> I did not realize I was a split personality <g>.
>>
>> Hmmmm - It didn't occur to me that you might be going to CPPCon.  So 
>> I guess I'll plan for three then.
>
> No I don't go to CPPCon but if you can get programmers to create 
> better documentation by your talk there I am all for it.
>
>>
>> Robert
>
>
> _______________________________________________
> Unsubscribe & other changes: 
> http://lists.boost.org/mailman/listinfo.cgi/boost