1SCHED_GET_PRIORITY_MAX(2) Linux Programmer's Manual SCHED_GET_PRIORITY_MAX(2)
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6 sched_get_priority_max, sched_get_priority_min - get static priority
7 range
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10 #include <sched.h>
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12 int sched_get_priority_max(int policy);
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14 int sched_get_priority_min(int policy);
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17 sched_get_priority_max() returns the maximum priority value that can be
18 used with the scheduling algorithm identified by policy.
19 sched_get_priority_min() returns the minimum priority value that can be
20 used with the scheduling algorithm identified by policy. Supported
21 policy values are SCHED_FIFO, SCHED_RR, SCHED_OTHER, and SCHED_BATCH.
22 Further details about these policies can be found in sched_setsched‐
23 uler(2).
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25 Processes with numerically higher priority values are scheduled before
26 processes with numerically lower priority values. Thus, the value
27 returned by sched_get_priority_max() will be greater than the value
28 returned by sched_get_priority_min().
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30 Linux allows the static priority value range 1 to 99 for SCHED_FIFO and
31 SCHED_RR and the priority 0 for SCHED_OTHER and SCHED_BATCH. Schedul‐
32 ing priority ranges for the various policies are not alterable.
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34 The range of scheduling priorities may vary on other POSIX systems,
35 thus it is a good idea for portable applications to use a virtual pri‐
36 ority range and map it to the interval given by sched_get_prior‐
37 ity_max() and sched_get_priority_min(). POSIX.1-2001 requires a spread
38 of at least 32 between the maximum and the minimum values for
39 SCHED_FIFO and SCHED_RR.
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41 POSIX systems on which sched_get_priority_max() and sched_get_prior‐
42 ity_min() are available define _POSIX_PRIORITY_SCHEDULING in
43 <unistd.h>.
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46 On success, sched_get_priority_max() and sched_get_priority_min()
47 return the maximum/minimum priority value for the named scheduling pol‐
48 icy. On error, -1 is returned, and errno is set appropriately.
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51 EINVAL The argument policy does not identify a defined scheduling pol‐
52 icy.
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55 POSIX.1-2001.
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58 sched_getaffinity(2), sched_getparam(2), sched_getscheduler(2),
59 sched_setaffinity(2), sched_setparam(2), sched_setscheduler(2)
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61 Programming for the real world - POSIX.4 by Bill O. Gallmeister,
62 O'Reilly & Associates, Inc., ISBN 1-56592-074-0.
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65 This page is part of release 3.53 of the Linux man-pages project. A
66 description of the project, and information about reporting bugs, can
67 be found at http://www.kernel.org/doc/man-pages/.
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71Linux 2006-03-23 SCHED_GET_PRIORITY_MAX(2)