Function return type style

Question

I'm learning c++0x, at least the parts supported by the Visual C++ Express 2010 Beta. This is a question about style rather than how it works. Perhaps it's too early for style and good practice to have evolved yet for a standard that isn't even released yet...

In c++0x you can define the return type of a method using -> type at the end of the function instead of putting the type at the start. I believe this change in syntax is required due to lambdas and some use cases of the new decltype keyword, but you can use it anywhere as far as I know.

// Old style 
int add1(int a, int b)
{
 return a + b;
}

// New style return type
auto add2(int a, int b) -> int
{
 return a + b;
}

My question really then, is given that some functions will need to be defined in the new way is it considered good style to define all functions in this way for consistency? Or should I stick to only using it when necessary?

Answer 1

Do not be style-consistent just for being consistent. Code should be readable, i.e. understandable, that's the only real measure. Adding clutter to 95% of the methods to be consistent with the other 5%, well, that just does not sound right to me.

Answer 2

There is a huge codebase that uses the 'old'/current rules. I would bet that is going to be so for a long time. The problem of consistency is two-fold: who are you going to be consistent with, the few code that will require the new syntax or all existing code?

I will keep with the old syntax when the new one is not required for a bit, but then again, only time will tell what becomes the common usage.

Also note that the new syntax is still a little weird: you declare the return type as auto and then define what auto means at the end of the signature declaration... It does not feel natural (even if you do not compare it with your own experience)