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System Calls - Manual Reference Pages  - RR_GET_INTERVAL (2)

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sched_rr_get_interval - get the SCHED_RR interval for the named process

CONTENTS

Synopsis
Description
Errors
Bugs

--> #include <sched.h>

int sched_rr_get_interval(pid_t pid, struct timespec *tp);

struct timespec {
    time_t  tv_sec;     /* seconds */
    long    tv_nsec;    /* nanoseconds */
};

sched_rr_get_interval() writes into the timespec structure pointed to by tp the round robin time quantum for the process identified by pid. If pid is zero, the time quantum for the calling process is written into *tp. The identified process should be running under the SCHED_RR scheduling policy.

The round robin time quantum value is not alterable under Linux 1.3.81.

POSIX systems on which sched_rr_get_interval() is available define _POSIX_PRIORITY_SCHEDULING in <unistd.h>.

On success, sched_rr_get_interval() returns 0. On error, -1 is returned, and errno is set appropriately.

EFAULT	Problem with copying information to userspace.
EINVAL	Invalid pid.
ENOSYS	The system call is not yet implemented.
ESRCH	The process whose ID is pid could not be found.

POSIX.1-2001.

As of Linux 1.3.81 sched_rr_get_interval() returns with error ENOSYS, because SCHED_RR has not yet been fully implemented and tested properly.

sched_setscheduler(2) has a description of the Linux scheduling scheme.

Programming for the real world - POSIX.4 by Bill O. Gallmeister, O’Reilly & Associates, Inc., ISBN 1-56592-074-0 or go to Top of page |  Section 2 |  Main Man Index.