sched_get_priority_max()

Arguments:

policy

The scheduling policy, which must be one of:

• SCHED_FIFO — a fixed-priority scheduler in which the highest priority ready thread runs until it blocks or is preempted by a higher priority thread.
• SCHED_RR — similar to SCHED_FIFO, except that threads at the same priority level timeslice (round robin) every 4 × the clock period (see ClockPeriod()).
• SCHED_OTHER — currently the same as SCHED_RR.
• SCHED_SPORADIC — sporadic scheduling. For more information, see pthread_attr_setschedpolicy(), and Scheduling policies in the chapter on the microkernel in the System Architecture guide.
• SCHED_HIGH_PRIORITY_IST — a FIFO scheduling policy that allows a thread to go at or above the clock IST, but below 255.
  Note:

  The SCHED_HIGH_PRIORITY_IST policy is intended only for ISTs. For more information, see Interrupt Service Thread (IST) in the Programmer's Guide.
• SCHED_OFFLINING — a FIFO scheduling policy intended for CPU offlining that allows a thread to be of higher priority than the clock IST.
  Note:

  • To set the SCHED_OFFLINING policy, the process must have the runstate ability enabled. For more information, go to Abilities in the QNX OS System Security Guide.
  • The offlining and onlining scheduling feature is experimental.

Library:

libc

Use the -l c option to qcc to link against this library. This library is usually included automatically.

Description:

The sched_get_priority_max() function returns the maximum value for the scheduling policy specified by policy.

Returns:

The appropriate maximum for success, or -1 (errno is set).

Errors:

EINVAL

The value of the policy parameter doesn't represent a defined scheduling policy.

ENOSYS

The sched_get_priority_max() function isn't currently supported.

Examples:

See sched_getparam().

Classification:

POSIX 1003.1 PS|TPS