nice(3)nice(3)Namenice - set program priority
Syntax
int nice(incr)
int incr;
Description
The scheduling priority of the process is augmented by incr. Positive
priorities get less service than normal. Priority 10 is recommended to
users who wish to execute long-running programs without flack from the
administration.
Negative increments are ignored except on behalf of the super-user.
The priority is limited to the range -20 (most urgent) to 20 (least).
The priority of a process is passed to a child process by For a privi‐
leged process to return to normal priority from an unknown state,
should be called successively with arguments -40 (goes to priority -20
because of truncation), 20 (to get to 0), then 0 (to maintain compati‐
bility with previous versions of this call).
Environment
In any mode, nice returns -1 and sets on an error. On success, the
return value depends on the mode in which your program was compiled.
In POSIX or System V mode, it is the new priority; otherwise, it is
zero. Note that, in POSIX and System V mode, -1 can indicate either
success or failure; must be used to determine which.
See Alsonice(1), fork(2), setpriority(2), renice(8)nice(3)