Playing with C++11 (using Clang)

Ale

I have been following the new C++ standard for quite some time (even before it was named C++11), so I’m very glad to see support for it reaching mainstream compilers such as clang, g++ and Visual C++.

Although this article here provides a good comparison of the state of the C++11 implementation in these three compilers, I wanted to give Clang on OSX a spin to see for myself how much of the new standard is actually supported in “real life” today.

I tried writing a short program that tested different features. I wasn’t expecting everything to work but, I was surprised to learn that some features that I was giving for granted are not widely available yet in clang 3.2 nor 4.0 .

Here’s my test program. It stores the numbers from 0 to 99 in a vector and then prints them to the console.


#include <algorithm>
#include <iostream>
#include <vector>

int main(int argc, char* argv[])
{
	// Create and populate a container:
	
	const int n = 100;
	std::vector<float> v(n);
	for (auto i = 0; i < n; i++)
	{
		v[i] = i;
	}
	
	// Iterate over v, applying a lambda expression on
	// each element.
	
	std::for_each(v.begin(), v.end(), [](int f) {
				std::cout << f << " ";
			});

	std::cout << std::endl;

	return 0;
}

Some new C++11 features used in this program are:

  1. New std::for_each for iterating over a vector.
  2. New "auto" keyword semantics.
  3. Lambda Expressions (used here for printing elements).

Some features I wanted to try but are not yet supported in Clang 3.2, nor in Apple's Clang 4.0 are:

  1. Initializer Lists. Some people claim it is still not to be supported by Apple, but I couldn't get it to work on an open source build of Clang. Granted, I used 3.2. I should try building a newer clang perhaps even from trunk.
  2. std::begin() and std::end(), which should come with the updated Standard Library. It seems the STL implementation is not complete yet.

If I have time to try different compiler configurations, I might post the results here. All in all I'm happy with support reaching the mainstream and hope that I can start writing C++11 code in my next assignment.