1#include <unistd.h>
 2#include <errno.h>
 3#include <sys/resource.h>
 4#include <limits.h>
 5#include "syscall.h"
 6
 7int nice(int inc)
 8{
 9	int prio = inc;
10	// Only query old priority if it can affect the result.
11	// This also avoids issues with integer overflow.
12	if (inc > -2*NZERO && inc < 2*NZERO)
13		prio += getpriority(PRIO_PROCESS, 0);
14	if (prio > NZERO-1) prio = NZERO-1;
15	if (prio < -NZERO) prio = -NZERO;
16	if (setpriority(PRIO_PROCESS, 0, prio)) {
17		if (errno == EACCES)
18			errno = EPERM;
19		return -1;
20	} else {
21		return prio;
22	}
23}