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[dragonfly.git] / lib / libc / sys / sched_get_priority_max.2
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984263bc 1.\" $FreeBSD: src/lib/libc/sys/sched_get_priority_max.2,v 1.3.2.9 2001/12/14 18:34:01 ru Exp $
44cb301e 2.\" $DragonFly: src/lib/libc/sys/sched_get_priority_max.2,v 1.3 2006/05/26 19:39:37 swildner Exp $
984263bc
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3.\" Copyright (c) 1998 HD Associates, Inc.
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27.Dd March 12, 1998
28.Dt SCHED_GET_PRIORITY_MAX 2
29.Os
30.Sh NAME
31.Nm sched_get_priority_max ,
32.Nm sched_get_priority_min ,
33.Nm sched_rr_get_interval
34.Nd get scheduling parameter limits
35.Sh LIBRARY
36.Lb libc
37.Sh SYNOPSIS
38.In sched.h
39.Ft int
40.Fn sched_get_priority_max "int policy"
41.Ft int
42.Fn sched_get_priority_min "int policy"
43.Ft int
44.Fn sched_rr_get_interval "pid_t pid" "struct timespec *interval"
45.Sh DESCRIPTION
46The
47.Fn sched_get_priority_max
48and
49.Fn sched_get_priority_min
50functions return the appropriate maximum or minimum, respectively,
51for the scheduling policy specified by
52.Fa policy .
53The
54.Fn sched_rr_get_interval
55function updates the
56.Fa timespec
57structure referenced by the
58.Fa interval
59argument to contain the current execution time limit (i.e., time
60quantum) for the process specified by
61.Fa pid .
62If
63.Fa pid
64is zero, the current execution time limit for the calling process is
65returned.
66.Pp
67The value of
68.Fa policy
69should be one of the scheduling policy values defined in
44cb301e 70.In sched.h :
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71.Bl -tag -width [SCHED_OTHER]
72.It Bq Er SCHED_FIFO
73First-in-first-out fixed priority scheduling with no round robin scheduling;
74.It Bq Er SCHED_OTHER
75The standard time sharing scheduler;
76.It Bq Er SCHED_RR
77Round-robin scheduling across same priority processes.
78.El
79.Sh RETURN VALUES
80If successful, the
81.Fn sched_get_priority_max
82and
83.Fn sched_get_priority_min
84functions shall return the appropriate maximum or minimum values,
85respectively. If unsuccessful, they shall return a value of -1 and set
86.Fa errno
87to indicate the error.
88.Pp
89.Rv -std sched_rr_get_interval
90.Sh ERRORS
91On failure
92.Va errno
93will be set to the corresponding value:
94.Bl -tag -width Er
95.It Bq Er EINVAL
96The value of the
97.Fa policy
98parameter does not represent a defined scheduling policy.
99.It Bq Er ENOSYS
100The
101.Fn sched_get_priority_max ,
102.Fn sched_get_priority_min ,
103and
104.Fn sched_rr_get_interval
105functions are not supported by the implementation.
106.It Bq Er ESRCH
107No process can be found corresponding to that specified by
108.Fa pid .
109.El
110.Sh SEE ALSO
111.Xr sched_getparam 2 ,
112.Xr sched_getscheduler 2 ,
113.Xr sched_setparam 2 ,
114.Xr sched_setscheduler 2
115.Sh STANDARDS
116The
117.Fn sched_setscheduler
118and
119.Fn sched_getscheduler
120functions conform to
121.St -p1003.1b-93 .