compiler-rt/lib/tsan/lit_tests/simple_race.cc

// RUN: %clangxx_tsan -O1 %s -o %t && %t 2>&1 | FileCheck %s
#include <pthread.h>
#include <stdio.h>

int Global;

void *Thread1(void *x) {
  Global++;
  return NULL;
}

void *Thread2(void *x) {
  Global--;
  return NULL;
}

int main() {
  pthread_t t[2];
  pthread_create(&t[0], NULL, Thread1, NULL);
  pthread_create(&t[1], NULL, Thread2, NULL);
  pthread_join(t[0], NULL);
  pthread_join(t[1], NULL);
}

// CHECK: WARNING: ThreadSanitizer: data race