NAME
nice —
change process scheduling
priority
SYNOPSIS
#include
<unistd.h>
int
nice(int
incr);
DESCRIPTION
The
nice()
function adds the value specified in incr to the
scheduling priority of the invoking process.
incr is an integer such that the resulting scheduling priority is within the range -20 to 20. Priority values outside this range are truncated to the appropriate limit. The default priority is 0; lower priorities cause more favorable scheduling. Only the superuser may lower priorities.
Children inherit the priority of their parent processes via fork(2).
RETURN VALUES
On success, nice() returns the new
priority. On error, it returns -1.
Since nice() can legitimately return the
value -1, it is necessary to clear the external variable
errno prior to the call, then check it afterward to
determine if a -1 is an error or a legitimate value.
ERRORS
nice() has the same failure conditions as
setpriority(2).
SEE ALSO
HISTORY
A nice() system call first appeared in
Version 3 AT&T UNIX. It has accepted an
incr argument since Version 4
AT&T UNIX.