Moving KDots to KDE Review

Ian Wadham at
Fri Apr 10 07:47:06 BST 2015

Hi Minh,

On 09/04/2015, at 9:11 PM, Minh Ngo wrote:
> Possibly it's because of the different stdlib (clang in Linux requires gcc, but on Mac maybe it uses other stdlib
> implementation), but I'm not sure about Mac. Is it possible to treat these errors as warnings?
> In the point.hpp the thing I did is just implemented a class Point that consists from two coordinates and a hash function to store it in std::unordered_*. Therefore please be free to change and don't fear about breaking logic :).

I suspect now that I am not getting a C++11 version of std lib in my build,
as is required for templated hash and std::unordered_set.  At least, when
I do make -k, to go past the errors regarding std::hash, at some point I get:

In file included from /kdedev/kde4m/kdesrc/kde/kdegames/kdots/polygonfinder.cpp:26:
/kdedev/kde4m/kdesrc/kde/kdegames/kdots/polygonfinder.hpp:29:10: fatal error: 
      'unordered_set' file not found
#include <unordered_set>

Something like this came up on the MacPorts Developers' list about 3 weeks
ago.  It appears that there is no uniform way to configure a C++11 compiler
and corresponding std lib across the various Apple OS X platforms supported
by MacPorts (e.g. 4.6 through to 4.10, spanning about 7 years of OS X releases).
The discussion was mostly way over my head, re Apple and MacPorts technology,
so I hope I did not misunderstand the main issue.

Before I dive in at the deep end on the Mac lists and perhaps give rise to another long
thread, may I ask some questions about KDots' coding and KDE Policy re C++11?.

Q1. Is it really necessary to use the std library directly in KDots?

Q2. Why does not KDots use Qt classes for points, hashes, containers, etc?
       Using Qt is the usual way to make KDE Games portable.

Q3. Is there any C++11 source code in KDots?

And for KF5 developers in general:

Q4. Is KDE Community code beginning to use C++11 and versions of std lib that
       have C++11 as a dependency?  What is the KDE Policy on this?

Cheers, Ian W.

> On 9 April 2015 at 12:25, Ian Wadham < at> wrote:
> Possibly the Clang compiler is picking up the wrong stdlib from somewhere or
> maybe Clang does not like the mix of namespace and template features in this
> particular code.  Can it be paraphrased and simplified in some way?
> It is similar to the final coding example in,
> so it ought to compile OK, but it is not exactly the same.  I might try modifying point.hpp
> to be textually and syntactically more like the example, without changing semantics.
> Another possibility is for me to try MacPorts' (Open Source) Clang, rather than Apple's,
> but I use Apple's Clang successfully for all other code.  Or I might be able to revert to
> MacPorts' gcc.

More information about the kde-core-devel mailing list