glibc/time/sys/time.h

/* Copyright (C) 1991,92,93,94,96,97,98,99 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 Library General Public License as
   published by the Free Software Foundation; either version 2 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
   Library General Public License for more details.

   You should have received a copy of the GNU Library General Public
   License along with the GNU C Library; see the file COPYING.LIB.  If not,
   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
   Boston, MA 02111-1307, USA.  */

#ifndef _SYS_TIME_H
#define _SYS_TIME_H	1

#include <features.h>

#include <time.h>
#include <sys/select.h>

#define __need_timeval
#include <bits/time.h>


__BEGIN_DECLS

/* 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;                           \
}


/* 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   This is obsolete and should never be used.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.  */
  };

/* Get the current time of day and timezone information,
   putting it into *TV and *TZ.  If TZ is NULL, *TZ is not filled.
   Returns 0 on success, -1 on errors.
   NOTE: This form of timezone information is obsolete.
   Use the functions and variables declared in <time.h> instead.  */
extern int gettimeofday (struct timeval *__tv, struct timezone *__tz) __THROW;

/* Set the current time of day and timezone information.
   This call is restricted to the super-user.  */
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;


/* 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;
  };

/* Set *VALUE to the current setting of timer WHICH.
   Return 0 on success, -1 on errors.  */
extern int getitimer (enum __itimer_which __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 (enum __itimer_which __which,
		      __const struct itimerval *__new,
		      struct itimerval *__old) __THROW;

/* Change the access time of FILE to TVP[0] and
   the modification time of FILE to TVP[1].  */
extern int utimes (__const char *__file, struct timeval __tvp[2]) __THROW;


/* 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)

__END_DECLS

#endif /* sys/time.h */