126 lines
3.7 KiB
Groff
126 lines
3.7 KiB
Groff
.\" $FreeBSD$
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.\" Copyright (c) 1998 HD Associates, Inc.
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.\" All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.Dd March 12, 1998
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.Dt SCHED_GET_PRIORITY_MAX 2
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.Os
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.Sh NAME
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.Nm sched_get_priority_max ,
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.Nm sched_get_priority_min ,
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.Nm sched_rr_get_interval
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.Nd get scheduling parameter limits
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.Sh LIBRARY
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.Lb libc
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.Sh SYNOPSIS
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.Fd #include <sched.h>
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.Ft int
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.Fn sched_get_priority_max "int policy"
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.Ft int
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.Fn sched_get_priority_min "int policy"
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.Ft int
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.Fn sched_rr_get_interval "pid_t pid" "struct timespec *interval"
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.Sh DESCRIPTION
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The
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.Fn sched_get_priority_max
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and
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.Fn sched_get_priority_min
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functions return the appropriate maximum or minimum, respectively,
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for the scheduling policy specified by
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.Fa policy .
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The
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.Fn sched_rr_get_interval
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function updates the
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.Fa timespec
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structure referenced by the
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.Fa interval
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argument to contain the current execution time limit (i.e., time
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quantum) for the process specified by
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.Fa pid .
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If
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.Fa pid
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is zero, the current execution time limit for the calling process is
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returned.
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.Pp
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The value of
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.Fa policy
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should be one of the scheduling policy values defined in
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.Fa <sched.h> :
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.Bl -tag -width [SCHED_OTHER]
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.It Bq Er SCHED_FIFO
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First-in-first-out fixed priority scheduling with no round robin scheduling;
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.It Bq Er SCHED_OTHER
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The standard time sharing scheduler;
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.It Bq Er SCHED_RR
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Round-robin scheduling across same priority processes.
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.El
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.Sh RETURN VALUES
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If successful, the
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.Fn sched_get_priority_max
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and
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.Fn sched_get_priority_min
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functions shall return the appropriate maximum or minimum values,
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respectively. If unsuccessful, they shall return a value of -1 and set
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.Fa errno
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to indicate the error.
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.Pp
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If successful, the
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.Fn sched_rr_get_interval
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function will return 0. Otherwise, it will
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return a value of -1 and set
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.Fa errno
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to indicate the error.
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.Sh ERRORS
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On failure
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.Va errno
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will be set to the corresponding value:
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.Bl -tag -width Er
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.It Bq Er EINVAL
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The value of the
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.Fa policy
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parameter does not represent a defined scheduling policy.
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.It Bq Er ENOSYS
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The
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.Fn sched_get_priority_max ,
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.Fn sched_get_priority_min ,
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and
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.Fn sched_rr_get_interval
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functions are not supported by the implementation.
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.It Bq Er ESRCH
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No process can be found corresponding to that specified by
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.Fa pid .
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.El
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.Sh SEE ALSO
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.Xr sched_getparam 2 ,
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.Xr sched_getscheduler 2 ,
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.Xr sched_setparam 2 ,
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.Xr sched_setscheduler 2
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.Sh STANDARDS
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The
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.Fn sched_setscheduler
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and
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.Fn sched_getscheduler
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functions conform to
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.St -p1003.1b-93 .
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