time/sys/time.h

   1 /* Copyright (C) 1991-2017 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <http://www.gnu.org/licenses/>.  */
  17
  18 #ifndef _SYS_TIME_H
  19 #define _SYS_TIME_H     1
  20
  21 #include <features.h>
  22
  23 #include <bits/types.h>
  24 #include <bits/types/time_t.h>
  25 #include <bits/types/struct_timeval.h>
  26
  27 #ifndef __suseconds_t_defined
  28 typedef __suseconds_t suseconds_t;
  29 # define __suseconds_t_defined
  30 #endif
  31
  32 #include <sys/select.h>
  33
  34 __BEGIN_DECLS
  35
  36 #ifdef __USE_GNU
  37 /* Macros for converting between `struct timeval' and `struct timespec'.  */
  38 # define TIMEVAL_TO_TIMESPEC(tv, ts) {                                   \
  39         (ts)->tv_sec = (tv)->tv_sec;                                    \
  40         (ts)->tv_nsec = (tv)->tv_usec * 1000;                           \
  41 }
  42 # define TIMESPEC_TO_TIMEVAL(tv, ts) {                                   \
  43         (tv)->tv_sec = (ts)->tv_sec;                                    \
  44         (tv)->tv_usec = (ts)->tv_nsec / 1000;                           \
  45 }
  46 #endif
  47
  48
  49 #ifdef __USE_MISC
  50 /* Structure crudely representing a timezone.
  51    This is obsolete and should never be used.  */
  52 struct timezone
  53   {
  54     int tz_minuteswest;         /* Minutes west of GMT.  */
  55     int tz_dsttime;             /* Nonzero if DST is ever in effect.  */
  56   };
  57
  58 typedef struct timezone *__restrict __timezone_ptr_t;
  59 #else
  60 typedef void *__restrict __timezone_ptr_t;
  61 #endif
  62
  63 /* Get the current time of day and timezone information,
  64    putting it into *TV and *TZ.  If TZ is NULL, *TZ is not filled.
  65    Returns 0 on success, -1 on errors.
  66    NOTE: This form of timezone information is obsolete.
  67    Use the functions and variables declared in <time.h> instead.  */
  68 extern int gettimeofday (struct timeval *__restrict __tv,
  69                          __timezone_ptr_t __tz) __THROW __nonnull ((1));
  70
  71 #ifdef __USE_MISC
  72 /* Set the current time of day and timezone information.
  73    This call is restricted to the super-user.  */
  74 extern int settimeofday (const struct timeval *__tv,
  75                          const struct timezone *__tz)
  76      __THROW;
  77
  78 /* Adjust the current time of day by the amount in DELTA.
  79    If OLDDELTA is not NULL, it is filled in with the amount
  80    of time adjustment remaining to be done from the last `adjtime' call.
  81    This call is restricted to the super-user.  */
  82 extern int adjtime (const struct timeval *__delta,
  83                     struct timeval *__olddelta) __THROW;
  84 #endif
  85
  86
  87 /* Values for the first argument to `getitimer' and `setitimer'.  */
  88 enum __itimer_which
  89   {
  90     /* Timers run in real time.  */
  91     ITIMER_REAL = 0,
  92 #define ITIMER_REAL ITIMER_REAL
  93     /* Timers run only when the process is executing.  */
  94     ITIMER_VIRTUAL = 1,
  95 #define ITIMER_VIRTUAL ITIMER_VIRTUAL
  96     /* Timers run when the process is executing and when
  97        the system is executing on behalf of the process.  */
  98     ITIMER_PROF = 2
  99 #define ITIMER_PROF ITIMER_PROF
 100   };
 101
 102 /* Type of the second argument to `getitimer' and
 103    the second and third arguments `setitimer'.  */
 104 struct itimerval
 105   {
 106     /* Value to put into `it_value' when the timer expires.  */
 107     struct timeval it_interval;
 108     /* Time to the next timer expiration.  */
 109     struct timeval it_value;
 110   };
 111
 112 #if defined __USE_GNU && !defined __cplusplus
 113 /* Use the nicer parameter type only in GNU mode and not for C++ since the
 114    strict C++ rules prevent the automatic promotion.  */
 115 typedef enum __itimer_which __itimer_which_t;
 116 #else
 117 typedef int __itimer_which_t;
 118 #endif
 119
 120 /* Set *VALUE to the current setting of timer WHICH.
 121    Return 0 on success, -1 on errors.  */
 122 extern int getitimer (__itimer_which_t __which,
 123                       struct itimerval *__value) __THROW;
 124
 125 /* Set the timer WHICH to *NEW.  If OLD is not NULL,
 126    set *OLD to the old value of timer WHICH.
 127    Returns 0 on success, -1 on errors.  */
 128 extern int setitimer (__itimer_which_t __which,
 129                       const struct itimerval *__restrict __new,
 130                       struct itimerval *__restrict __old) __THROW;
 131
 132 /* Change the access time of FILE to TVP[0] and the modification time of
 133    FILE to TVP[1].  If TVP is a null pointer, use the current time instead.
 134    Returns 0 on success, -1 on errors.  */
 135 extern int utimes (const char *__file, const struct timeval __tvp[2])
 136      __THROW __nonnull ((1));
 137
 138 #ifdef __USE_MISC
 139 /* Same as `utimes', but does not follow symbolic links.  */
 140 extern int lutimes (const char *__file, const struct timeval __tvp[2])
 141      __THROW __nonnull ((1));
 142
 143 /* Same as `utimes', but takes an open file descriptor instead of a name.  */
 144 extern int futimes (int __fd, const struct timeval __tvp[2]) __THROW;
 145 #endif
 146
 147 #ifdef __USE_GNU
 148 /* Change the access time of FILE relative to FD to TVP[0] and the
 149    modification time of FILE to TVP[1].  If TVP is a null pointer, use
 150    the current time instead.  Returns 0 on success, -1 on errors.  */
 151 extern int futimesat (int __fd, const char *__file,
 152                       const struct timeval __tvp[2]) __THROW;
 153 #endif
 154
 155
 156 #ifdef __USE_MISC
 157 /* Convenience macros for operations on timevals.
 158    NOTE: `timercmp' does not work for >= or <=.  */
 159 # define timerisset(tvp)        ((tvp)->tv_sec || (tvp)->tv_usec)
 160 # define timerclear(tvp)        ((tvp)->tv_sec = (tvp)->tv_usec = 0)
 161 # define timercmp(a, b, CMP)                                                  \
 162   (((a)->tv_sec == (b)->tv_sec) ?                                             \
 163    ((a)->tv_usec CMP (b)->tv_usec) :                                          \
 164    ((a)->tv_sec CMP (b)->tv_sec))
 165 # define timeradd(a, b, result)                                               \
 166   do {                                                                        \
 167     (result)->tv_sec = (a)->tv_sec + (b)->tv_sec;                             \
 168     (result)->tv_usec = (a)->tv_usec + (b)->tv_usec;                          \
 169     if ((result)->tv_usec >= 1000000)                                         \
 170       {                                                                       \
 171         ++(result)->tv_sec;                                                   \
 172         (result)->tv_usec -= 1000000;                                         \
 173       }                                                                       \
 174   } while (0)
 175 # define timersub(a, b, result)                                               \
 176   do {                                                                        \
 177     (result)->tv_sec = (a)->tv_sec - (b)->tv_sec;                             \
 178     (result)->tv_usec = (a)->tv_usec - (b)->tv_usec;                          \
 179     if ((result)->tv_usec < 0) {                                              \
 180       --(result)->tv_sec;                                                     \
 181       (result)->tv_usec += 1000000;                                           \
 182     }                                                                         \
 183   } while (0)
 184 #endif  /* Misc.  */
 185
 186 __END_DECLS
 187
 188 #endif /* sys/time.h */