glibc/sysdeps/unix/nice.c

46 lines
1.4 KiB
C

/* Copyright (C) 1992, 1996 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., 675 Mass Ave,
Cambridge, MA 02139, USA. */
#include <errno.h>
#include <unistd.h>
#include <sys/resource.h>
/* Increment the scheduling priority of the calling process by INCR.
The superuser may use a negative INCR to decrement the priority. */
int
nice (incr)
int incr;
{
int save;
int prio;
/* -1 is a valid priority, so we use errno to check for an error. */
save = errno;
__set_errno (0);
prio = getpriority (PRIO_PROCESS, 0);
if (prio == -1)
{
if (errno != 0)
return -1;
else
__set_errno (save);
}
return setpriority (PRIO_PROCESS, 0, prio + incr);
}