HarmonyOS async/await promise是在哪个线程，如何判断主线程还是子线程

import process from '@ohos.process'; 
function isMainThread(): boolean { 
  return process.pid == process.tid 
}

#include <unistd.h> 
#include <thread> 
#include <sys/syscall.h> 
  bool isMainThread() { 
  pid_t pid = getpid(); 
  pid_t tid = syscall(SYS_gettid); 
  if (pid == tid) { 
    return true; 
  } else { 
    return false; 
  } 
}