HP-UX Reference (11i v1 00/12) - 2 System Calls (vol 5)

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STANDARD Printed by: Nora Chuang [nchuang] STANDARD

/build/1111/BRICK/man2/!!!intro.2

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rtprio(2) rtprio(2)

by pid.

[EPERM] The group access list of the calling process does not contain a group having

PRIV_RTPRIO capability and prio is not RTPRIO_NOCHG, or

RTPRIO_RTOFF with a pid of zero.

[ESRCH] No process can be found corresponding to that speciﬁed by pid.

EXAMPLES

The following call to rtprio() sets the calling process to a real-time priority of 90:

rtprio(0, 90);

WARNINGS

Normally, compute-bound programs should not be run at real-time priorities, because all timesharing work

on the CPU would come to a complete halt.

DEPENDENCIES

Series 800

Because processes executing at real-time priorities get scheduling preference over a system process execut-

ing at a lower priority, unexpected system behavior can occur after a power failure on systems that support

power-fail recovery. For example, when init (see init(1M)) receives the powerfail signal SIGPWR, it nor-

mally reloads programmable hardware such as terminal multiplexers. If a higher-priority real-time process

is eligible to run after the power failure, the running of

init is delayed. This condition temporarily

prevents terminal input to any process, including real-time shells of higher priority than the eligible real-

time process. To avoid this situation, a real-time process should catch SIGPWR and suspend itself until

init has ﬁnished its powerfail processing.

AUTHOR

rtprio() was developed by HP.