Re: [boost] CMake and Boost Build tests

Subject: Re: [boost] CMake and Boost Build tests
From: Edward Diener (eldiener_at_[hidden])
Date: 2017-07-27 08:24:52

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.

> 
> 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