NetBSD/share/man/man3/param.3

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.\" $NetBSD: param.3,v 1.4 2011/04/10 10:02:34 jruoho Exp $
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.\" Copyright (c) 2011 Jukka Ruohonen <jruohonen@iki.fi>
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.Dd April 10, 2011
.Dt PARAM 3
.Os
.Sh NAME
.Nm param
.Nd common parameters
.Sh SYNOPSIS
.In sys/param.h
.Ft size
.Fn MAX "size a" "size b"
.Ft size
.Fn MIN "size a" "size b"
.Sh DESCRIPTION
The
.In sys/param.h
header includes some common definitions and macros specific to
.Nx .
The header is perhaps best characterized as a kernel equivalent of
.In sys/types.h .
The following list summarizes the provided definitions and macros.
.Bl -bullet -offset indent
.It
First and foremost, the header defines the version of
.Nx .
This is defined as
.Bd -literal -offset indent
#define __NetBSD_Version__ 599004800 /* 5.99.48 */
.Ed
.Pp
The general format is
.Dq MMmmrrpp00 ,
where
.Sq MM
and
.Sq mm
denote the major and minor version, respectively,
.Sq rr
is provided for compatibility, and
.Sq pp
defines the patch level.
.It
Common utility macros such as
.Fn MAX
and
.Fn MIN
as well as more specific macros such as
.Xr STACK 9 ,
.Xr ctod 9 ,
.Xr mstohz 9 ,
.Xr roundup 9 ,
and
.Xr setbit 9 .
.It
Numerous miscellaneous definitions such as limits,
constants for the kernel
.Xr memoryallocators 9 ,
scale factors used by the scheduler,
.Xr kthread 9
priorities, and many others.
.It
Definitions provided for historical and compatibility reasons.
Examples range from definitions such as
.Dq #define BSD
to old priority levels used in the kernel.
.El
.Sh SEE ALSO
.Xr bitops 3 ,
.Xr cdefs 3 ,
.Xr types 3 ,
.Xr unistd 3
.Sh HISTORY
A
.In param.h
header appeared already in the
.At v4 .