NAME

     sched_get_priority_max, sched_get_priority_min, sched_rr_get_interval — get scheduling
     parameter limits

LIBRARY

     Standard C Library (libc, -lc)

SYNOPSIS

     #include <sched.h>

     int
     sched_get_priority_max(int policy);

     int
     sched_get_priority_min(int policy);

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

DESCRIPTION

     The sched_get_priority_max() and sched_get_priority_min() system calls return the
     appropriate maximum or minimum, respectively, for the scheduling policy specified by policy.
     The sched_rr_get_interval() system call updates the timespec structure referenced by the
     interval argument to contain the current execution time limit (i.e., time quantum) for the
     process specified by pid.  If pid is zero, the current execution time limit for the calling
     process is returned.

     The value of policy should be one of the scheduling policy values defined in <sched.h>:

     [SCHED_FIFO]   First-in-first-out fixed priority scheduling with no round robin scheduling;

     [SCHED_OTHER]  The standard time sharing scheduler;

     [SCHED_RR]     Round-robin scheduling across same priority processes.

RETURN VALUES

     If successful, the sched_get_priority_max() and sched_get_priority_min() system calls shall
     return the appropriate maximum or minimum values, respectively.  If unsuccessful, they shall
     return a value of -1 and set errno to indicate the error.

     The sched_rr_get_interval() 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

     On failure errno will be set to the corresponding value:

     [EINVAL]           The value of the policy argument does not represent a defined scheduling
                        policy.

     [ENOSYS]           The sched_get_priority_max(), sched_get_priority_min(), and
                        sched_rr_get_interval() system calls are not supported by the
                        implementation.

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

SEE ALSO

     sched_getparam(2), sched_getscheduler(2), sched_setparam(2), sched_setscheduler(2)

STANDARDS

     The sched_get_priority_max(), sched_get_priority_min(), and sched_rr_get_interval() system
     calls conform to IEEE Std 1003.1b-1993 (“POSIX.1”).