/usr/ucb/cc [ flag ... ] file ... #include<unistd.h> int nice(incr) int incr;
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 privileged 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).
Upon successful completion, nice() returns 0. Otherwise, a value of -1 is returned and errno is set to indicate the error.
The priority is not changed if:
cc(1B), nice(1), renice(1), fork(2), priocntl(2), getpriority(3C)
Use of these interfaces should be restricted to only applications written on BSD platforms. Use of these interfaces with any of the system libraries or in multi-threaded applications is unsupported.