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RTPRIO(2) BSD System Calls Manual RTPRIO(2) NAME rtprio -- examine or modify a process realtime or idle priority LIBRARY Standard C Library (libc, -lc) SYNOPSIS #include <sys/types.h> #include <sys/rtprio.h> int rtprio(int function, pid_t pid, struct rtprio *rtp); DESCRIPTION rtprio() is used to lookup or change the realtime or idle priority of a process. function specifies the operation to be performed. RTP_LOOKUP to lookup the current priority, and RTP_SET to set the priority. pid specifies the process to be used, 0 for the current process. *rtp is a pointer to a struct rtprio which is used to specify the prior- ity and priority type. This structure has the following form: struct rtprio { u_short type; u_short prio; }; The value of the type field may be RTP_PRIO_REALTIME for realtime priori- ties, RTP_PRIO_NORMAL for normal priorities, and RTP_PRIO_IDLE for idle priorities. The priority specified by the prio field ranges between 0 and RTP_PRIO_MAX (usually 31). 0 is the highest possible priority. Realtime and idle priority is inherited through fork() and exec(). A realtime process can only be preempted by a process of equal or higher priority, or by an interrupt; idle priority processes will run only when no other real/normal priority process is runnable. Higher real/idle pri- ority processes preempt lower real/idle priority processes. Processes of equal real/idle priority are run round-robin. RETURN VALUES The rtprio() function returns the value 0 if successful; otherwise the value -1 is returned and the global variable errno is set to indicate the error. ERRORS rtprio() will fail if [EINVAL] The specified prio was out of range. [EPERM] The calling process is not allowed to set the realtime priority. Only root is allowed to change the realtime priority of any process, and non-root may only change the idle priority of the current process. [ESRCH] The specified process was not found. AUTHORS The original author was Henrik Vestergaard Draboel <hvd@terry.ping.dk>. This implementation in FreeBSD was substantially rewritten by David Greenman. SEE ALSO nice(1), ps(1), rtprio(1), setpriority(2), nice(3), renice(8) BSD July 23, 1994 BSD
NAME | LIBRARY | SYNOPSIS | DESCRIPTION | RETURN VALUES | ERRORS | AUTHORS | SEE ALSO
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