1  /* timespec -- System time interface
       2  
       3     Copyright (C) 2000, 2002, 2004-2005, 2007, 2009-2022 Free Software
       4     Foundation, Inc.
       5  
       6     This file is free software: you can redistribute it and/or modify
       7     it under the terms of the GNU Lesser General Public License as
       8     published by the Free Software Foundation, either version 3 of the
       9     License, or (at your option) any later version.
      10  
      11     This file is distributed in the hope that it will be useful,
      12     but WITHOUT ANY WARRANTY; without even the implied warranty of
      13     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
      14     GNU Lesser General Public License for more details.
      15  
      16     You should have received a copy of the GNU Lesser General Public License
      17     along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
      18  
      19  #if ! defined TIMESPEC_H
      20  #define TIMESPEC_H
      21  
      22  #include <time.h>
      23  
      24  #ifndef _GL_INLINE_HEADER_BEGIN
      25   #error "Please include config.h first."
      26  #endif
      27  _GL_INLINE_HEADER_BEGIN
      28  #ifndef _GL_TIMESPEC_INLINE
      29  # define _GL_TIMESPEC_INLINE _GL_INLINE
      30  #endif
      31  
      32  #ifdef __cplusplus
      33  extern "C" {
      34  #endif
      35  
      36  #include "arg-nonnull.h"
      37  
      38  /* Inverse resolution of timespec timestamps (in units per second),
      39     and log base 10 of the inverse resolution.  */
      40  
      41  enum { TIMESPEC_HZ = 1000000000 };
      42  enum { LOG10_TIMESPEC_HZ = 9 };
      43  
      44  /* Obsolescent names for backward compatibility.
      45     They are misnomers, because TIMESPEC_RESOLUTION is not a resolution.  */
      46  
      47  enum { TIMESPEC_RESOLUTION = TIMESPEC_HZ };
      48  enum { LOG10_TIMESPEC_RESOLUTION = LOG10_TIMESPEC_HZ };
      49  
      50  /* Return a timespec with seconds S and nanoseconds NS.  */
      51  
      52  _GL_TIMESPEC_INLINE struct timespec
      53  make_timespec (time_t s, long int ns)
      54  {
      55    struct timespec r;
      56    r.tv_sec = s;
      57    r.tv_nsec = ns;
      58    return r;
      59  }
      60  
      61  /* Return negative, zero, positive if A < B, A == B, A > B, respectively.  */
      62  
      63  _GL_TIMESPEC_INLINE int _GL_ATTRIBUTE_PURE
      64  timespec_cmp (struct timespec a, struct timespec b)
      65  {
      66    return 2 * _GL_CMP (a.tv_sec, b.tv_sec) + _GL_CMP (a.tv_nsec, b.tv_nsec);
      67  }
      68  
      69  /* Return -1, 0, 1, depending on the sign of A.  A.tv_nsec must be
      70     nonnegative.  */
      71  _GL_TIMESPEC_INLINE int _GL_ATTRIBUTE_PURE
      72  timespec_sign (struct timespec a)
      73  {
      74    return _GL_CMP (a.tv_sec, 0) + (!a.tv_sec & !!a.tv_nsec);
      75  }
      76  
      77  struct timespec timespec_add (struct timespec, struct timespec)
      78    _GL_ATTRIBUTE_CONST;
      79  struct timespec timespec_sub (struct timespec, struct timespec)
      80    _GL_ATTRIBUTE_CONST;
      81  struct timespec dtotimespec (double)
      82    _GL_ATTRIBUTE_CONST;
      83  
      84  /* Return an approximation to A, of type 'double'.  */
      85  _GL_TIMESPEC_INLINE double
      86  timespectod (struct timespec a)
      87  {
      88    return a.tv_sec + a.tv_nsec / 1e9;
      89  }
      90  
      91  long int gettime_res (void);
      92  struct timespec current_timespec (void);
      93  void gettime (struct timespec *) _GL_ARG_NONNULL ((1));
      94  int settime (struct timespec const *) _GL_ARG_NONNULL ((1));
      95  
      96  #ifdef __cplusplus
      97  }
      98  #endif
      99  
     100  _GL_INLINE_HEADER_END
     101  
     102  #endif