C++0x in ICC 11

Intel is advancing faster than GNU in support the upcoming C++0x. The two features I expect most, auto declaration and lambda function, have both been supported satisfactorily. Lambda functions that use variables defined outside (output_and_sum in the following demo) are supported as well as simpler ones (add in the following demo).

#include <cstdio>
#include <algorithm>
using namespace std;
 
int main()
{
    static const int myvec[] = { 1, 2, 3, 4, 5 };
 
    int sum = 0;
    auto add = [] (int a, int b) -> int { return a+b; };
    auto output_and_sum = [&sum,add](int x) { sum  = add(sum,x); printf ("%d\n", x); };
    for_each (myvec, myvec+5, output_and_sum);
    printf ("sum = %d\n", sum);
}

(I use printf instead of cout merely to make the assembly list more readable.)

ICC compiles this program (an option -std=c++0x is necessary, of course) and gives the correct resuls:

1
2
3
4
5
sum = 15

Also the two lambda functions are well inlined and optimized – variable sum, which is used by the lambda function by reference, is completely stored in a register, though it is easy to find several useless instructions in the assembly dump.

Some other less important (in my view) features (e.g. initializer_list) are not implemented yet. (BTW, I really had a hard time finding the “request noncommercial free license” link on Intel’s website, while I could see the link to “buy a commercial license” everywhere..)

Hopefully C++0x will be more successful than C99, which is filled with ugly and nobody-wants-to-implement features.

Related posts:

1. An Rvalue Reference Issue
2. GCC #pragma pack bug
3. C++0x draft finished
4. Floating point exception
5. Difference between dup(0) and open(“/dev/fd/0″,…);

Tags: C++0x, C/C++, ICC