source: CIVL/examples/languageFeatures/atomicStatement.cvl

/* Commandline execution:
 *              civl verify -inputB=3 atomicStatement.cvl
 * */
#include<civlc.cvh>
$input int B = 3;
$input int N;
$assume(0<N && N<B);
int n = 3;

void main(){
  int x;
  
  $atomic{
    $when(n > 1) n = 3;
    $atomic{
      x = N;
      x = x * 2;
    }
    $assert(x == 2*N);
    // non-determinism allowed in $atomic block
    $atomic{
      x = 3;
      $choose {
        $when (n>2) { x=2;  }
        $when (n>1) { x=1;  }
        default: {x=0;  }
      }
    }
    $assert(x == 2 || x == 1);
  }
}