sysdeps/unix/sysv/linux/getpriority.c

   1 /* getpriority for Linux.
   2    Copyright (C) 1996, 1998 Free Software Foundation, Inc.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Library General Public License as
   6    published by the Free Software Foundation; either version 2 of the
   7    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    Library General Public License for more details.
  13
  14    You should have received a copy of the GNU Library General Public
  15    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  16    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  17    Boston, MA 02111-1307, USA.  */
  18
  19 #include <errno.h>
  20 #include <sys/resource.h>
  21
  22 #include <sysdep.h>
  23 #include <sys/syscall.h>
  24
  25 extern int __syscall_getpriority (int, int);
  26
  27 /* The return value of __syscall_getpriority is biased by this value
  28    to avoid returning negative values.  */
  29 #define PZERO 20
  30
  31 /* Return the highest priority of any process specified by WHICH and WHO
  32    (see above); if WHO is zero, the current process, process group, or user
  33    (as specified by WHO) is used.  A lower priority number means higher
  34    priority.  Priorities range from PRIO_MIN to PRIO_MAX.  */
  35
  36 int
  37 getpriority (enum __priority_which which, int who)
  38 {
  39   int res;
  40
  41   res = INLINE_SYSCALL (getpriority, 2, (int) which, who);
  42   if (res >= 0)
  43     res = PZERO - res;
  44   return res;
  45 }