text: /* systime.h - System-dependent definitions for time manipulations.
     Copyright (C) 1993, 1994 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 2, 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., 59 Temple Place - Suite 330,
  Boston, MA 02111-1307, USA.  */
  
  #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 long 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
  
  /* 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 iff 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 iff 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 */
  #define EMACS_GET_TIME(time)					\
  {								\
    struct timezone dummy;					\
    gettimeofday (&(time), &dummy);				\
  }
  #endif /* not GETTIMEOFDAY_ONE_ARGUMENT */
  
  #define EMACS_ADD_TIME(dest, src1, src2)			\
  {								\
    (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++;			\
  }
  
  #define EMACS_SUB_TIME(dest, src1, src2)			\
  {								\
    (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--;			\
  }
  
  #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 ();
  