source: CIVL/examples/pthread/esbmc/sigma_false-unreach-call.c@ 1aaefd4

extern void __VERIFIER_error() __attribute__ ((__noreturn__));

#include <stdlib.h>
#include <pthread.h>
#include <string.h>

void __VERIFIER_assert(int expression) { if (!expression) { ERROR: __VERIFIER_error();}; return; }

const int SIGMA = 16;

int *array;
int array_index=-1;


void *thread(void * arg)
{
        array[array_index] = 1;
        return 0;
}


int main()
{
        int tid, sum;
        pthread_t *t;

        t = (pthread_t *)malloc(sizeof(pthread_t) * SIGMA);
        array = (int *)malloc(sizeof(int) * SIGMA);

        __VERIFIER_assume(t);
        __VERIFIER_assume(array);

        for (tid=0; tid<SIGMA; tid++) {
                array_index++;
                pthread_create(&t[tid], 0, thread, 0);
        }

        for (tid=0; tid<SIGMA; tid++) {
                pthread_join(t[tid], 0);
        }

        for (tid=sum=0; tid<SIGMA; tid++) {
                sum += array[tid];
        }

        __VERIFIER_assert(sum == SIGMA);  // <-- wrong, different threads might use the same array offset when writing

        return 0;
}