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Languguage OS II Version 10-94 (Knowledge Media)(1994).ISO
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shllutil.lha
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shellutils-1.8
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nice.c
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1991-12-07
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/* nice -- run a program with modified scheduling priority
Copyright (C) 1990, 1991 Free Software Foundation, Inc.
This program 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.
This program 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 this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
/* David MacKenzie <djm@ai.mit.edu> */
#include <stdio.h>
#include <getopt.h>
#include <sys/types.h>
#ifndef NICE_PRIORITY
#include <sys/time.h>
#include <sys/resource.h>
#endif
#include "system.h"
int isinteger ();
void error ();
void usage ();
/* The name this program was run with. */
char *program_name;
struct option longopts[] =
{
{"adjustment", 1, NULL, 'n'},
{NULL, 0, NULL, 0}
};
void
main (argc, argv)
int argc;
char **argv;
{
int current_priority;
int adjustment = 0;
int minusflag = 0;
int adjustment_given = 0;
int optc;
program_name = argv[0];
while ((optc = getopt_long (argc, argv, "+0123456789-n:", longopts,
(int *) 0)) != EOF)
{
switch (optc)
{
case '?':
usage ();
case 'n':
if (!isinteger (optarg))
error (1, 0, "invalid priority `%s'", optarg);
adjustment = atoi (optarg);
adjustment_given = 1;
break;
case '-':
minusflag = 1;
break;
default:
adjustment = adjustment * 10 + optc - '0';
adjustment_given = 1;
}
}
if (minusflag)
adjustment = -adjustment;
if (!adjustment_given)
adjustment = 10;
if (optind == argc)
{
if (adjustment_given)
usage ();
/* No command given; print the priority. */
errno = 0;
#ifndef NICE_PRIORITY
current_priority = getpriority (PRIO_PROCESS, 0);
#else
current_priority = nice (0);
#endif
if (current_priority == -1 && errno != 0)
error (1, errno, "cannot get priority");
printf ("%d\n", current_priority);
exit (0);
}
errno = 0;
#ifndef NICE_PRIORITY
current_priority = getpriority (PRIO_PROCESS, 0);
#else
current_priority = nice (0);
#endif
if (current_priority == -1 && errno != 0)
error (1, errno, "cannot get priority");
#ifndef NICE_PRIORITY
if (setpriority (PRIO_PROCESS, 0, current_priority + adjustment))
#else
if (nice (adjustment) == -1)
#endif
error (1, errno, "cannot set priority");
execvp (argv[optind], &argv[optind]);
error (errno == ENOENT ? 127 : 126, errno, "%s", argv[optind]);
}
/* Return nonzero if S represents a (possibly signed) decimal integer,
zero if not. */
int
isinteger (s)
char *s;
{
if (*s == '-')
++s;
if (*s == 0)
return 0;
while (*s)
{
if (*s < '0' || *s > '9')
return 0;
++s;
}
return 1;
}
void
usage ()
{
fprintf (stderr, "\
Usage: %s [-n adjustment] [-adjustment] [--adjustment=adjustment]\n\
[command [arg...]]\n",
program_name);
exit (1);
}