clock.hpp 2.5 KB

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  1. /*
  2. Copyright (c) 2007-2016 Contributors as noted in the AUTHORS file
  3. This file is part of libzmq, the ZeroMQ core engine in C++.
  4. libzmq is free software; you can redistribute it and/or modify it under
  5. the terms of the GNU Lesser General Public License (LGPL) as published
  6. by the Free Software Foundation; either version 3 of the License, or
  7. (at your option) any later version.
  8. As a special exception, the Contributors give you permission to link
  9. this library with independent modules to produce an executable,
  10. regardless of the license terms of these independent modules, and to
  11. copy and distribute the resulting executable under terms of your choice,
  12. provided that you also meet, for each linked independent module, the
  13. terms and conditions of the license of that module. An independent
  14. module is a module which is not derived from or based on this library.
  15. If you modify this library, you must extend this exception to your
  16. version of the library.
  17. libzmq is distributed in the hope that it will be useful, but WITHOUT
  18. ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  19. FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
  20. License for more details.
  21. You should have received a copy of the GNU Lesser General Public License
  22. along with this program. If not, see <http://www.gnu.org/licenses/>.
  23. */
  24. #ifndef __ZMQ_CLOCK_HPP_INCLUDED__
  25. #define __ZMQ_CLOCK_HPP_INCLUDED__
  26. #include "macros.hpp"
  27. #include "stdint.hpp"
  28. #if defined ZMQ_HAVE_OSX
  29. // TODO this is not required in this file, but condition_variable.hpp includes
  30. // clock.hpp to get these definitions
  31. #ifndef CLOCK_REALTIME
  32. #define CLOCK_REALTIME 0
  33. #endif
  34. #ifndef HAVE_CLOCK_GETTIME
  35. #define HAVE_CLOCK_GETTIME
  36. #endif
  37. #include <mach/clock.h>
  38. #include <mach/mach.h>
  39. #include <time.h>
  40. #include <sys/time.h>
  41. #endif
  42. namespace zmq
  43. {
  44. class clock_t
  45. {
  46. public:
  47. clock_t ();
  48. // CPU's timestamp counter. Returns 0 if it's not available.
  49. static uint64_t rdtsc ();
  50. // High precision timestamp.
  51. static uint64_t now_us ();
  52. // Low precision timestamp. In tight loops generating it can be
  53. // 10 to 100 times faster than the high precision timestamp.
  54. uint64_t now_ms ();
  55. private:
  56. // TSC timestamp of when last time measurement was made.
  57. uint64_t _last_tsc;
  58. // Physical time corresponding to the TSC above (in milliseconds).
  59. uint64_t _last_time;
  60. ZMQ_NON_COPYABLE_NOR_MOVABLE (clock_t)
  61. };
  62. }
  63. #endif