判断和退出

void die(const char *reason)
{
  fprintf(stderr, "%s\n", reason);
  exit(EXIT_FAILURE);
}

#define TEST_NZ(x) do { if ( (x)) die("error: " #x " failed (returned non-zero)." ); } while (0)
#define TEST_Z(x)  do { if (!(x)) die("error: " #x " failed (returned zero/null)."); } while (0)

 if (argc != 3)
    die("usage: client <server-address> <server-port>");

  TEST_NZ(getaddrinfo(argv[1], argv[2], NULL, &addr));

  TEST_Z(ec = rdma_create_event_channel());