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We were lucky enough to start a new project ~1 year ago - completely in C++11. We make heavy use of all the new fun C++11 stuff like lambdas, move constructors

We were lucky enough to start a new project ~1 year ago - completely in C++11. We make heavy use of all the new fun C++11 stuff like lambdas, move constructors (yay, no vectors of pointers anymore!) and all that auto/decltype syntactic sugar. And I must say: It's a whole different programming language and a new level of productivity.

forrestthewoods 14y ago
Depending on move constructors scare the bajeezus out of me because I have no way of knowing if it's working properly. It's behavior is also implementation specific. Given the following test you'll get a variety of results depending on your platform. struct Foo{...} std::vector<Foo> vec; for( int i = 0; i < 10; ++i) { vec.push_back( Foo() ); } Results: 35 move / 25 copy / 10 move + 15 copy / 25 move. It all depends on your compiler and STL implementation. Not knowing scares the hell out of me.
- shawn-butler 14y ago
  I don't understand your comment. Please try the following: vec.reserve(10); and report back how many allocations occur.
- CJefferson 14y ago
  I assume what you are saying is the following? * Compilers are introducing move as we move in C++11. If you compile your code in C++03 (or a compiler with partial C++11 support, no move). * The standard doesn't place a strict definition on how vectors are increased in size as you push_back. Of course, if you want to control the amount of space in a vector manually, rather than let your compiler decide, you can reserve in advance. Is your problem just with moving to C++11, or do you get different numbers (other than different numbers of moves) in a compiler with proper C++11 support (basically, the most recent version of everything).
- ksherlock 14y ago
  You could also look into emplace_back() http://en.cppreference.com/w/cpp/container/vector/emplace_back http://en.cppreference.com/w/cpp/container/vector/emplace_ba...
shawn-butler 14y ago
At this point assuming your team makeup hasn't changed much, have you been able to generate any intesting metrics to guage the increase in productivity? Also what compiler did you feel comfortable picking a year ago to base a production development effort on?

forrestthewoods 14y ago

Depending on move constructors scare the bajeezus out of me because I have no way of knowing if it's working properly. It's behavior is also implementation specific. Given the following test you'll get a variety of results depending on your platform. struct Foo{...} std::vector<Foo> vec; for( int i = 0; i < 10; ++i) { vec.push_back( Foo() ); } Results: 35 move / 25 copy / 10 move + 15 copy / 25 move. It all depends on your compiler and STL implementation. Not knowing scares the hell out of me.

shawn-butler 14y ago
I don't understand your comment. Please try the following: vec.reserve(10); and report back how many allocations occur.
CJefferson 14y ago
I assume what you are saying is the following? * Compilers are introducing move as we move in C++11. If you compile your code in C++03 (or a compiler with partial C++11 support, no move). * The standard doesn't place a strict definition on how vectors are increased in size as you push_back. Of course, if you want to control the amount of space in a vector manually, rather than let your compiler decide, you can reserve in advance. Is your problem just with moving to C++11, or do you get different numbers (other than different numbers of moves) in a compiler with proper C++11 support (basically, the most recent version of everything).
ksherlock 14y ago
You could also look into emplace_back() http://en.cppreference.com/w/cpp/container/vector/emplace_back http://en.cppreference.com/w/cpp/container/vector/emplace_ba...

shawn-butler 14y ago

At this point assuming your team makeup hasn't changed much, have you been able to generate any intesting metrics to guage the increase in productivity? Also what compiler did you feel comfortable picking a year ago to base a production development effort on?