glibc/time/sys/time.h

/* Copyright (C) 1991-2021 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <https://www.gnu.org/licenses/>.  */

#ifndef _SYS_TIME_H
#define _SYS_TIME_H	1

#include <features.h>

#include <bits/types.h>
#include <bits/types/time_t.h>
#include <bits/types/struct_timeval.h>

#ifndef __suseconds_t_defined
typedef __suseconds_t suseconds_t;
# define __suseconds_t_defined
#endif

#include <sys/select.h>

__BEGIN_DECLS

#ifdef __USE_GNU
/* Macros for converting between `struct timeval' and `struct timespec'.  */
# define TIMEVAL_TO_TIMESPEC(tv, ts) {                                   \
	(ts)->tv_sec = (tv)->tv_sec;                                    \
	(ts)->tv_nsec = (tv)->tv_usec * 1000;                           \
}
# define TIMESPEC_TO_TIMEVAL(tv, ts) {                                   \
	(tv)->tv_sec = (ts)->tv_sec;                                    \
	(tv)->tv_usec = (ts)->tv_nsec / 1000;                           \
}
#endif


#ifdef __USE_MISC
/* Structure crudely representing a timezone.
   This is obsolete and should never be used.  */
struct timezone
  {
    int tz_minuteswest;		/* Minutes west of GMT.  */
    int tz_dsttime;		/* Nonzero if DST is ever in effect.  */
  };
#endif

/* Get the current time of day, putting it into *TV.
   If TZ is not null, *TZ must be a struct timezone, and both fields
   will be set to zero.
   Calling this function with a non-null TZ is obsolete;
   use localtime etc. instead.
   This function itself is semi-obsolete;
   most callers should use time or clock_gettime instead. */
extern int gettimeofday (struct timeval *__restrict __tv,
			 void *__restrict __tz) __THROW __nonnull ((1));

#ifdef __USE_MISC
/* Set the current time of day and timezone information.
   This call is restricted to the super-user.
   Setting the timezone in this way is obsolete, but we don't yet
   warn about it because it still has some uses for which there is
   no alternative.  */
extern int settimeofday (const struct timeval *__tv,
			 const struct timezone *__tz)
     __THROW;

/* Adjust the current time of day by the amount in DELTA.
   If OLDDELTA is not NULL, it is filled in with the amount
   of time adjustment remaining to be done from the last `adjtime' call.
   This call is restricted to the super-user.  */
extern int adjtime (const struct timeval *__delta,
		    struct timeval *__olddelta) __THROW;
#endif


/* Values for the first argument to `getitimer' and `setitimer'.  */
enum __itimer_which
  {
    /* Timers run in real time.  */
    ITIMER_REAL = 0,
#define ITIMER_REAL ITIMER_REAL
    /* Timers run only when the process is executing.  */
    ITIMER_VIRTUAL = 1,
#define ITIMER_VIRTUAL ITIMER_VIRTUAL
    /* Timers run when the process is executing and when
       the system is executing on behalf of the process.  */
    ITIMER_PROF = 2
#define ITIMER_PROF ITIMER_PROF
  };

/* Type of the second argument to `getitimer' and
   the second and third arguments `setitimer'.  */
struct itimerval
  {
    /* Value to put into `it_value' when the timer expires.  */
    struct timeval it_interval;
    /* Time to the next timer expiration.  */
    struct timeval it_value;
  };

#if defined __USE_GNU && !defined __cplusplus
/* Use the nicer parameter type only in GNU mode and not for C++ since the
   strict C++ rules prevent the automatic promotion.  */
typedef enum __itimer_which __itimer_which_t;
#else
typedef int __itimer_which_t;
#endif

/* Set *VALUE to the current setting of timer WHICH.
   Return 0 on success, -1 on errors.  */
extern int getitimer (__itimer_which_t __which,
		      struct itimerval *__value) __THROW;

/* Set the timer WHICH to *NEW.  If OLD is not NULL,
   set *OLD to the old value of timer WHICH.
   Returns 0 on success, -1 on errors.  */
extern int setitimer (__itimer_which_t __which,
		      const struct itimerval *__restrict __new,
		      struct itimerval *__restrict __old) __THROW;

/* Change the access time of FILE to TVP[0] and the modification time of
   FILE to TVP[1].  If TVP is a null pointer, use the current time instead.
   Returns 0 on success, -1 on errors.  */
extern int utimes (const char *__file, const struct timeval __tvp[2])
     __THROW __nonnull ((1));

#ifdef __USE_MISC
/* Same as `utimes', but does not follow symbolic links.  */
extern int lutimes (const char *__file, const struct timeval __tvp[2])
     __THROW __nonnull ((1));

/* Same as `utimes', but takes an open file descriptor instead of a name.  */
extern int futimes (int __fd, const struct timeval __tvp[2]) __THROW;
#endif

#ifdef __USE_GNU
/* Change the access time of FILE relative to FD to TVP[0] and the
   modification time of FILE to TVP[1].  If TVP is a null pointer, use
   the current time instead.  Returns 0 on success, -1 on errors.  */
extern int futimesat (int __fd, const char *__file,
		      const struct timeval __tvp[2]) __THROW;
#endif


#ifdef __USE_MISC
/* Convenience macros for operations on timevals.
   NOTE: `timercmp' does not work for >= or <=.  */
# define timerisset(tvp)	((tvp)->tv_sec || (tvp)->tv_usec)
# define timerclear(tvp)	((tvp)->tv_sec = (tvp)->tv_usec = 0)
# define timercmp(a, b, CMP) 						      \
  (((a)->tv_sec == (b)->tv_sec) 					      \
   ? ((a)->tv_usec CMP (b)->tv_usec) 					      \
   : ((a)->tv_sec CMP (b)->tv_sec))
# define timeradd(a, b, result)						      \
  do {									      \
    (result)->tv_sec = (a)->tv_sec + (b)->tv_sec;			      \
    (result)->tv_usec = (a)->tv_usec + (b)->tv_usec;			      \
    if ((result)->tv_usec >= 1000000)					      \
      {									      \
	++(result)->tv_sec;						      \
	(result)->tv_usec -= 1000000;					      \
      }									      \
  } while (0)
# define timersub(a, b, result)						      \
  do {									      \
    (result)->tv_sec = (a)->tv_sec - (b)->tv_sec;			      \
    (result)->tv_usec = (a)->tv_usec - (b)->tv_usec;			      \
    if ((result)->tv_usec < 0) {					      \
      --(result)->tv_sec;						      \
      (result)->tv_usec += 1000000;					      \
    }									      \
  } while (0)
#endif	/* Misc.  */

__END_DECLS

#endif /* sys/time.h */