[mapserver-dev] Modernizing code base: C99 and maybe C++ ?

Seth G sethg at geographika.co.uk
Wed Nov 27 06:15:45 PST 2019

On the C89/99 choice, I've not written enough of either to have an opinion so 1++ on whatever you think is best for the future of the project. 

I think with a version 8 we should also consider:

- upping the minimum required versions of all dependencies - the page here [1] is likely out of date
- increase minimum CMake version
- increase minimum SWIG version
- drop Python2 support
- drop deprecated Mapfile keywords

There are probably several other features/options that should be considered for deprecation/dropping. 


[1] https://mapserver.org/installation/unix.html#required-external-libraries

twitter: @geographika

On Wed, Nov 27, 2019, at 12:43 AM, Even Rouault wrote:
> Hi,
> the kind of topics that is always controversial, but I do think this is a 
> matter of survival for the project. I can write C89 code for sure, but which 
> bad thing did I do to still be obliged to do it :-) ? Should new contributors 
> be constrained by that... 2020 is just in a few days :-)
> Do we have a strong reason to stay with C89 for our .c files ? Not being able 
> to use for loop initial declarations ( that is "for( int i = 0; i < ... ; ++)" 
> ) is the example of something really annoying. Or being able to put 
> declarations in the middle of a function instead of putting them at the 
> beginning of it. This makes code harder to read, maintain and more error prone 
> because of potential accidental reuse of variables that shouldn't.
> All gcc and clang compilers from the last 10 years support C99. Regarding 
> MSVC, MSVC >= 2015 has decent enough support of it. Do we need to support 
> older MSVC versions ? I don't think so. Neither current GDAL nor PROJ can 
> built with older versions 
> For the record, PROJ requires C99 for its few remaining .c files (and C++11 
> for .cpp. So does GDAL)
> Next topic would be a
> for i in *.c; do mv $i "`basename $i .c`.cpp"; done
> Well, maybe not like that, because I'm expecting a ton of warnings. But more 
> on a case by case basis where someone needs to do non-trivial changes in part 
> of the code.
> Being constrained by C deeply sucks honesty. Apart from the Linux kernel which 
> still resists for good reasons, I can't think of a single one for MapServer.
> The main point where C sucks is string manipulation, and MapServer does a ton 
> of it. Being able to use std::string would be such a relief.
> Ah for the record, we do have C++ in the code base: mapogr.cpp and the agg 
> renderer.
> Even
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