%description:
test evaluation order.
plain C++ version:

  #include <iostream>
  using namespace std;

  int x=0;

  int f() {return ++x;}

  int main()
  {
      cout << f() << " " << f() << endl;
      return 0;
  }

This strangely yields different results, even with the same
gcc version (but different architecture):
   Itanium 64 bit, SuSE Linux,    g++ 3.3.3 ---> 1 2
   x86     32 bit, Red Hat Linux, g++ 3.3.3 ---> 2 1

%global:
int x=0;
int f() {return ++x;}

%activity:
EV << f() << " " << f() << endl;

%contains-regex: stdout
(1 2)|(2 1)