source: CIVL/examples/pthread/cprover/11_fmaxsymopt_true.c@ 1aaefd4

#include <pthread.h>

#define assume(e) __VERIFIER_assume(e)
#define assert_nl(e) { if(!(e)) { goto ERROR; } }
#define assert(e) { if(!(e)) { ERROR: goto ERROR; (void)0; } }

#define WORKPERTHREAD 2
#define THREADSMAX 3
volatile int max = 0x80000000, m = 0;

void __VERIFIER_atomic_acquire()
{
        assume(m==0);
        m = 1;
}

void __VERIFIER_atomic_release()
{
        assume(m==1);
        m = 0;
}

int storage[WORKPERTHREAD*THREADSMAX];

inline void findMax(int offset){

        int i;
        int e;
        int my_max = 0x80000000;

        for(i = offset; i < offset+WORKPERTHREAD; i++) {
#ifndef NOBUG
                e = storage[i];
#else
    e = rand();
#endif

                if(e > my_max) {
                        my_max = e;
                }
                assert_nl(e <= my_max);
        }

        __VERIFIER_atomic_acquire();
        {
                if(my_max > max) {
                        max = my_max;
                }
        }
        __VERIFIER_atomic_release();

        assert(my_max <= max);
}

void* thr1(void* arg) {
        int offset;

        assume(offset % WORKPERTHREAD == 0 && offset >= 0 && offset < WORKPERTHREAD*THREADSMAX);
        //assume(offset < WORKPERTHREAD && offset >= 0 && offset < WORKPERTHREAD*THREADSMAX);

        findMax(offset);

  return 0;
}

int main(){
  pthread_t t;

        while(1) { pthread_create(&t, 0, thr1, 0); }
}