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It’s a great pity that Objective-C doesn’t get more attention in this regard. It’s C, so it features all the simplicity, elegance and existing APIs. And at the

by zoul 15y ago

It’s a great pity that Objective-C doesn’t get more attention in this regard. It’s C, so it features all the simplicity, elegance and existing APIs. And at the same time it offers a good, simple and flexible object model with almost no surprises. The performance can be very good, too, as proved by the Apple runtime, and you can always drop to lower-level tricks or plain C when you need it. The syntax takes some getting used to, but then turns into another advantage, since it’s very self-descriptive. Again, it’s a shame it gets so little attention outside the Apple world, because it would be a perfect match for many use cases.

cageface 15y ago
The problem is that Obj-C message passing is always going to have a cost. STL implementations can inline accessors, for instance, to provide containers and algorithms with essentially zero overhead that can even be faster than raw C because the compiler has more type information.
- zoul 15y ago
  That’s a non-issue for the vast majority of people. As an example, I have written games in Objective-C for the first iPhones. In a game running at 50 fps you have about 20 ms to get a single frame out, and still I could freely use message passing in the inner game loop without giving it a thought. See also some older measurements by Mike Ash: http://goo.gl/DBTPE http://goo.gl/DBTPE.
  - cageface 15y ago
    An Obj-C message is still about 5x slower than a C++ virtual function call, but even that is too slow for inner loops of expensive algorithms. For example, I'm doing DSP at 44.1k ops per second and I can only afford about one virtual function call for every sixteen samples but I can put my samples in an STL vector with no access overhead vs a raw array. It's true that most people don't need the performance you can get with C++ but if you do it's still really your only serious option.
    - zoul 15y ago
      According to Mike’s measurements I linked above a cached Objective-C message send is faster than C++ virtual method call, so in a loop both languages should come pretty close. You can also get a pointer to the function implementing a method and call it directly. But I think we now understand each other – yes, Objective-C is not as fast as C++ in some cases, but those cases only matter to a very small number of people.
      - rikthevik 15y ago
        Also, it's _really_ easy to optimize those inner loops if you need to in Objective-C. If message passing is too slow, just turn it into some C function calls and you're done.

by zoul 15y ago

cageface 15y ago

The problem is that Obj-C message passing is always going to have a cost. STL implementations can inline accessors, for instance, to provide containers and algorithms with essentially zero overhead that can even be faster than raw C because the compiler has more type information.

zoul 15y ago
That’s a non-issue for the vast majority of people. As an example, I have written games in Objective-C for the first iPhones. In a game running at 50 fps you have about 20 ms to get a single frame out, and still I could freely use message passing in the inner game loop without giving it a thought. See also some older measurements by Mike Ash: http://goo.gl/DBTPE http://goo.gl/DBTPE.
- cageface 15y ago
  An Obj-C message is still about 5x slower than a C++ virtual function call, but even that is too slow for inner loops of expensive algorithms. For example, I'm doing DSP at 44.1k ops per second and I can only afford about one virtual function call for every sixteen samples but I can put my samples in an STL vector with no access overhead vs a raw array. It's true that most people don't need the performance you can get with C++ but if you do it's still really your only serious option.
  - zoul 15y ago
    According to Mike’s measurements I linked above a cached Objective-C message send is faster than C++ virtual method call, so in a loop both languages should come pretty close. You can also get a pointer to the function implementing a method and call it directly. But I think we now understand each other – yes, Objective-C is not as fast as C++ in some cases, but those cases only matter to a very small number of people.
    - rikthevik 15y ago
      Also, it's _really_ easy to optimize those inner loops if you need to in Objective-C. If message passing is too slow, just turn it into some C function calls and you're done.