ClickHouse/libs/libcommon/include/common/apple_rt.h

#pragma once
/** Allows to build on MacOS X
  *
  * Highly experimental, not recommended, disabled by default.
  *
  * To use, include this file with -include compiler parameter.
  */

#ifdef __APPLE__

#include <common/config_common.h>

#if APPLE_SIERRA_OR_NEWER == 0
/**
 * MacOS X doesn't support different clock sources
 *
 * Mapping all of them to 0, except for
 * CLOCK_THREAD_CPUTIME_ID, because there is a way
 * to implement it using in-kernel stats about threads
 */
#define CLOCK_MONOTONIC_COARSE 0
#define CLOCK_REALTIME 0
#define CLOCK_MONOTONIC 0
#define CLOCK_THREAD_CPUTIME_ID 3

typedef int clockid_t;
int clock_gettime(int clk_id, struct timespec* t);
#else
#define CLOCK_MONOTONIC_COARSE CLOCK_MONOTONIC
#endif

#endif