Links to complete photo series: Steak Number Eight, The Galacticos and Roadburg.

Links to complete photo series: Arsenal, Mike Ladd and Balthazar.

Links to complete photo series: The Sedan Vault and Madensuyu.

#include <iostream>

struct A
{
	void fun(int x) { std::cout << "int A\n"; }
};

struct B: A
{
	void fun(float x) { std::cout << "float B\n"; }
};

int main()
{
	B b;
	b.fun(3);
	return 0;
}

What shall it print? If your answer is int A, you’re probably assuming that the compiler will choose the best possible overload between A::fun and B::fun. In that case however you’re ignoring an often overlooked rule called name hiding.

The truth is that when you declare a function in a derived class, any function in the parent class that goes by the same name will be hidden from B’s interface. From the C++ standard (C++ 98, 3.3.7 § 1): “A name can be hidden by an explicit declaration of that same name in a nested declarative region or derived class.” The consequence is that A::fun will never be considered as a possible overload, and only suitable function to call is B::fun. And so, the program will print float B.

Can it be fixed? Well, it depends on what you mean by “fixed”, as nothing is broken. But it surely is possible to bring back A’s fun into B’s interface so that it is considered as a potential overload again. One labourious way to do it is by declaring a new function in B that forwards the call to A:

// laborious solution
struct B: A
{
	void fun(int x) { A::fun(x); }
	void fun(float x) { std::cout << "float B\n"; }
};

However, if there are many fun overloads in A, and many different derived classes like B, this quickly gets very annoying …

A far more easier solution is the using-declaration (C++ 98, 7.3.3 and 10.2 § 2): “A using-declaration introduces a name into the declarative region in which the using-declaration appears. That name is a synonym for the name of some entity declared elsewhere.” It will declare A’s fun into B’s scope, and make it as such available as a potential overload:

// easier solution
struct B: A
{
	using A::fun;
	void fun(float x) { std::cout << "float B\n"; }
};

Now the compiler will also consider A::fun as a possible overload and print int A.

There are however a few cases in which the using-declaration won’t help: e.g. you can’t use it on constructors as they don’t have a name. For more details, see section 7.3.3 of the C++ 98 standard.

Team William is a funky indie pop band that mixes guitars with something that reminds me of 8-bit game consoles. It has an odd sound that I really like. They played on the small stage: no smoke and steady (mainly reddish) lights. Not perfect, but good enough for some nice shots. Some worked out better in black & white, because of the strong red colourcast.

Kawada is a formation around Joeri Cnapelinckx, playing somewhat more introspective tunes. Listen to Creating a bigger boat for an easy but very enjoyable song, or Fake license for a more fun fanfare-loaded track. They were the last band to ascend the big stage, and again it proofed quite hard to get any decent pics: too dark and too much smoke. Yet, of all bands on this stage, I like their pictures most.

The last band of the night was Roadburg. Sharing two members with The Galacticos, they are at least as cheerful, albeit jazzier. Which is nice. An old tube radio was featured as prop and apparently it is also very handy to put your drinks on.

Links to complete photo series: Team William, Kawada and Roadburg.

Most people using Python know how to format output using string interpolation. It works much like C’s sprintf, except for the funny % operator:

>>> a = "the Knights"
>>> b = "Ni"
>>> "we are %s who say %s" % (a, b)
'we are the Knights who say Ni'

What is less known is that you can replace the right hand argument by a dictionary and use its keys to tell what value goes where. That’s handy when you need to insert more than one or two in a string, or when a single value is used more than once. Especially for localisation strings, it gives you the flexibility to determine the when and where of the values in the string itself.

>>> "we are %(who)s who say %(what)s" % {"who": a, "what": b}
'we are the Knights who say Ni'

Combine that with the even lesser known function vars() which returns a dictionary of the local variables and their values:

>>> vars()
{'__builtins__': <module '__builtin__' (built-in)>, '__name__':
 '__main__', 'b': 'Ni', '__doc__': None, 'a': 'the Knights'}

Use it at the right hand, and you can simply use the variable names as keywords:

>>> "we are %(a)s who say %(b)s" % vars()
'we are the Knights who say Ni'

This probably is the closest you can get to the Perl and PHP style syntax "we are the $a who say $b".

Share and Enjoy!

The first band to hit the stage was The Galacticos: always in for a good show with happy rock and catchy melodies. In contrast to last time at Tank series, there was enough light at Trix to justify colour pictures. Though the excessive use of smoke made it quite difficult still. [photo series]

I’ve seen Arquettes playing before, but this was the first time I had my camera with. Though they played on the smaller stage with basic lights, I’m much more pleased with the results than of The Galacticos and Steak Number Eight. Is it the lack of smoke? Or the more static lighting flooding the stage? I’ve done quite a few black & white conversions as the red front lights almost always result in very ugly colour casts, even if you set your white balance at minimum colour temperature and drag down the red channel. But in some cases it was still acceptable. (photo series)

Next on the main stage was Steak Number Eight. I’ve seen them a number of times now and their slow and heavy wall of sound still impresses me. The seemingly mandatory thick cloud of smoke made it quite impossible to get the crisp shots I was after. And so I decided to play it a bit differently: desaturating the colours even further and upping the contrast, building up a grim atmosphere that fits their music. (photo series)

Links to complete photo series: The Galacticos, Arquettes, Steak Number Eight.

The light conditions couldn’t have been more different than on Blikfest: static and dim. Perfect conditions to try out my new Sigma 30mm f/1.4. And with a crowd as packed as in Du Gaz on that night, the wide angle 30mm was very welcome (well, technically, due to the crop factor, it actually is equivalent to the standard FOV).

Slow shutterspeeds, lots of motionblurred pictures, ugly colours only suitable for black and white. And yet, somehow I love it! I’m especially fond of the following detail of a microphone waiting on the floor with behind it a pair of feet tapping on the rhythm of the music:

Kudos to Piet for the hospitality and introduction to this wonderful band!

link to complete photo series