NAME

nice − change priority of a process

SYNOPSIS

nice(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 undue impact on system performance.

Negative increments are illegal, except when specified by the super-user.  The priority is limited to the range −20 (most urgent) to 20 (least).  Requests for values above or below these limits result in the scheduling priority being set to the corresponding limit. 

The priority of a process is passed to a child process by fork(2). For a privileged process to return to normal priority from an unknown state, nice should be called successively with arguments −40 (goes to priority −20 because of truncation), 20 (to get to 0), then 0 (to maintain compatibility with previous versions of this call). 

RETURN VALUE

Upon successful completion, nice returns 0.  Otherwise, a value of −1 is returned and errno is set to indicate the error. 

ERRORS

The priority is not changed if:

EACCES The value of incr specified was negative, and the effective user ID is not super-user. 

SEE ALSO

nice(1), getpriority(2), setpriority(2), fork(2), renice(8)

Sun Release 3.2  —  Last change: 22 May 1986