sysdeps/unix/bsd/times.c

   1 /* Copyright (C) 1991,92,93,95,96,97,1998,2001 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, write to the Free
  16    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  17    02111-1307 USA.  */
  18
  19 #include <errno.h>
  20 #include <stddef.h>
  21 #include <sys/resource.h>
  22 #include <sys/times.h>
  23 #include <sys/time.h>
  24 #include <time.h>
  25
  26
  27 /* Time the program started.  */
  28 extern time_t _posix_start_time;
  29
  30 #ifdef __GNUC__
  31 __inline
  32 #endif
  33 static clock_t
  34 timeval_to_clock_t (const struct timeval *tv, clock_t clk_tck)
  35 {
  36   return (clock_t) ((tv->tv_sec * clk_tck) +
  37                     (tv->tv_usec * clk_tck / 1000000L));
  38 }
  39
  40 /* Store the CPU time used by this process and all its
  41    dead children (and their dead children) in BUFFER.
  42    Return the elapsed real time, or (clock_t) -1 for errors.
  43    All times are in CLK_TCKths of a second.  */
  44 clock_t
  45 __times (buffer)
  46      struct tms *buffer;
  47 {
  48   struct rusage usage;
  49   clock_t clk_tck;
  50
  51   if (buffer == NULL)
  52     {
  53       __set_errno (EINVAL);
  54       return (clock_t) -1;
  55     }
  56
  57   clk_tck = __getclktck ();
  58
  59   if (__getrusage (RUSAGE_SELF, &usage) < 0)
  60     return (clock_t) -1;
  61   buffer->tms_utime = (clock_t) timeval_to_clock_t (&usage.ru_utime, clk_tck);
  62   buffer->tms_stime = (clock_t) timeval_to_clock_t (&usage.ru_stime, clk_tck);
  63
  64   if (__getrusage (RUSAGE_CHILDREN, &usage) < 0)
  65     return (clock_t) -1;
  66   buffer->tms_cutime = (clock_t) timeval_to_clock_t (&usage.ru_utime, clk_tck);
  67   buffer->tms_cstime = (clock_t) timeval_to_clock_t (&usage.ru_stime, clk_tck);
  68
  69   return (time ((time_t *) NULL) - _posix_start_time) * clk_tck;
  70 }
  71
  72 weak_alias (__times, times)