---
name: "sched_rr_get_interval"
section: "2freebsd"
platform: "linux"
package: "freebsd-manpages"
version: "12.2-2"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/sched_get_priority_max/2freebsd"
---

# sched\_rr\_get\_interval(2freebsd)

get scheduling parameter limits

Part of [sched\_get\_priority\_max(2freebsd)](/sched_get_priority_max/2freebsd.md).

## 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_getparam/2.md), [sched\_getscheduler(2)](/sched_getscheduler/2.md), [sched\_setparam(2)](/sched_setparam/2.md), [sched\_setscheduler(2)](/sched_setscheduler/2.md)

## 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.1b”).