Replace `iff' in comments.

[bpt/emacs.git] / src / systime.h

/* systime.h - System-dependent definitions for time manipulations.
   Copyright (C) 1993, 1994, 2002, 2003, 2004,
                 2005, 2006, 2007 Free Software Foundation, Inc.

This file is part of GNU Emacs.

GNU Emacs is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3, or (at your option)
any later version.

GNU Emacs 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 General Public License for more details.

You should have received a copy of the GNU General Public License
along with GNU Emacs; see the file COPYING.  If not, write to
the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
Boston, MA 02110-1301, USA.  */

#ifndef EMACS_SYSTIME_H
#define EMACS_SYSTIME_H

#ifdef TIME_WITH_SYS_TIME
#include <sys/time.h>
#include <time.h>
#else
#ifdef HAVE_SYS_TIME_H
#include <sys/time.h>
#else
#include <time.h>
#endif
#endif

#ifdef HAVE_TZNAME
#ifndef tzname		/* For SGI.  */
extern char *tzname[];	/* RS6000 and others want it this way.  */
#endif
#endif

/* SVr4 doesn't actually declare this in its #include files.  */
#ifdef USG5_4
extern time_t timezone;
#endif

#ifdef VMS
#ifdef VAXC
#include "vmstime.h"
#endif
#endif

/* On some configurations (hpux8.0, X11R4), sys/time.h and X11/Xos.h
   disagree about the name of the guard symbol.  */
#ifdef HPUX
#ifdef _STRUCT_TIMEVAL
#ifndef __TIMEVAL__
#define __TIMEVAL__
#endif
#endif
#endif
\f
/* EMACS_TIME is the type to use to represent temporal intervals -
   struct timeval on some systems, int on others.  It can be passed as
   the timeout argument to the select  system call.

   EMACS_SECS (TIME) is an rvalue for the seconds component of TIME.
   EMACS_SET_SECS (TIME, SECONDS) sets that to SECONDS.

   EMACS_HAS_USECS is defined if EMACS_TIME has a usecs component.
   EMACS_USECS (TIME) is an rvalue for the microseconds component of TIME.
   	This returns zero if EMACS_TIME doesn't have a microseconds component.
   EMACS_SET_USECS (TIME, MICROSECONDS) sets that to MICROSECONDS.
	This does nothing if EMACS_TIME doesn't have a microseconds component.

   EMACS_SET_SECS_USECS (TIME, SECS, USECS) sets both components of TIME.

   EMACS_GET_TIME (TIME) stores the current system time in TIME, which
	should be an lvalue.

   EMACS_ADD_TIME (DEST, SRC1, SRC2) adds SRC1 to SRC2 and stores the
	result in DEST.  SRC should not be negative.

   EMACS_SUB_TIME (DEST, SRC1, SRC2) subtracts SRC2 from SRC1 and
	stores the result in DEST.  SRC should not be negative.
   EMACS_TIME_NEG_P (TIME) is true if TIME is negative.

*/

#ifdef HAVE_TIMEVAL

#define EMACS_HAS_USECS

#define EMACS_TIME struct timeval
#define EMACS_SECS(time)		    ((time).tv_sec  + 0)
#define EMACS_USECS(time)		    ((time).tv_usec + 0)
#define EMACS_SET_SECS(time, seconds)	    ((time).tv_sec  = (seconds))
#define EMACS_SET_USECS(time, microseconds) ((time).tv_usec = (microseconds))

/* On SVR4, the compiler may complain if given this extra BSD arg.  */
#ifdef GETTIMEOFDAY_ONE_ARGUMENT
#define EMACS_GET_TIME(time) gettimeofday (&(time))
#else /* not GETTIMEOFDAY_ONE_ARGUMENT */
/* Presumably the second arg is ignored.  */
#define EMACS_GET_TIME(time) gettimeofday (&(time), NULL)
#endif /* not GETTIMEOFDAY_ONE_ARGUMENT */

#define EMACS_ADD_TIME(dest, src1, src2)		\
  do {							\
    (dest).tv_sec  = (src1).tv_sec  + (src2).tv_sec;	\
    (dest).tv_usec = (src1).tv_usec + (src2).tv_usec;	\
    if ((dest).tv_usec > 1000000)			\
      (dest).tv_usec -= 1000000, (dest).tv_sec++;	\
  } while (0)

#define EMACS_SUB_TIME(dest, src1, src2)		\
  do {							\
    (dest).tv_sec  = (src1).tv_sec  - (src2).tv_sec;	\
    (dest).tv_usec = (src1).tv_usec - (src2).tv_usec;	\
    if ((dest).tv_usec < 0)				\
      (dest).tv_usec += 1000000, (dest).tv_sec--;	\
  } while (0)

#define EMACS_TIME_NEG_P(time)					\
  ((long)(time).tv_sec < 0					\
   || ((time).tv_sec == 0					\
       && (long)(time).tv_usec < 0))

#else /* ! defined (HAVE_TIMEVAL) */

#define EMACS_TIME int
#define EMACS_SECS(time)		    (time)
#define EMACS_USECS(time)		    0
#define EMACS_SET_SECS(time, seconds)	    ((time) = (seconds))
#define EMACS_SET_USECS(time, usecs)	    0

#define EMACS_GET_TIME(t) ((t) = time ((long *) 0))
#define EMACS_ADD_TIME(dest, src1, src2) ((dest) = (src1) + (src2))
#define EMACS_SUB_TIME(dest, src1, src2) ((dest) = (src1) - (src2))
#define EMACS_TIME_NEG_P(t) ((t) < 0)

#endif /* ! defined (HAVE_TIMEVAL) */

#define EMACS_SET_SECS_USECS(time, secs, usecs) 		\
  (EMACS_SET_SECS (time, secs), EMACS_SET_USECS (time, usecs))

extern int set_file_times __P ((const char *, EMACS_TIME, EMACS_TIME));

/* defined in keyboard.c */
extern void set_waiting_for_input __P ((EMACS_TIME *));

/* When lisp.h is not included Lisp_Object is not defined (this can
   happen when this files is used outside the src directory).
   Use GCPRO1 to determine if lisp.h was included.  */
#ifdef GCPRO1
/* defined in dired.c */
extern Lisp_Object make_time __P ((time_t));
#endif

/* Compare times T1 and T2.  Value is 0 if T1 and T2 are the same.
   Value is < 0 if T1 is less than T2.  Value is > 0 otherwise.  */

#define EMACS_TIME_CMP(T1, T2)			\
  (EMACS_SECS (T1) - EMACS_SECS (T2)		\
   + (EMACS_SECS (T1) == EMACS_SECS (T2)	\
      ? EMACS_USECS (T1) - EMACS_USECS (T2)	\
      : 0))

/* Compare times T1 and T2 for equality, inequality etc.  */

#define EMACS_TIME_EQ(T1, T2) (EMACS_TIME_CMP (T1, T2) == 0)
#define EMACS_TIME_NE(T1, T2) (EMACS_TIME_CMP (T1, T2) != 0)
#define EMACS_TIME_GT(T1, T2) (EMACS_TIME_CMP (T1, T2) > 0)
#define EMACS_TIME_GE(T1, T2) (EMACS_TIME_CMP (T1, T2) >= 0)
#define EMACS_TIME_LT(T1, T2) (EMACS_TIME_CMP (T1, T2) < 0)
#define EMACS_TIME_LE(T1, T2) (EMACS_TIME_CMP (T1, T2) <= 0)

#endif /* EMACS_SYSTIME_H */

/* arch-tag: dcb79915-cf99-4bce-9778-aade71d07651
   (do not change this comment) */