110 lines
4.0 KiB
Groff
110 lines
4.0 KiB
Groff
.\" Copyright (c) 1983, 1991, 1993
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.\" The Regents of the University of California. 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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.\" 3. All advertising materials mentioning features or use of this software
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.\" must display the following acknowledgement:
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.\" This product includes software developed by the University of
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.\" California, Berkeley and its contributors.
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.\" 4. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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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.\" $FreeBSD$
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.\"
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.Dd December 13, 1995
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.Dt INTRO 9
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.Os FreeBSD 2.2
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.Sh NAME
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.Nm intro
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.Nd "introduction to system kernel interfaces"
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.Sh DESCRIPTION
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This section contains information about the interfaces and
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subroutines in the kernel.
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.Sh PROTOTYPES ANSI-C AND ALL THAT
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Yes please.
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.Pp
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We would like all code to be fully prototyped.
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.Pp
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If your code compiles cleanly with
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.Nm cc
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.Ar -Wall
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we would feel happy about it.
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It is important to understand that this isn't a question of just shutting up
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.Nm cc ,
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it is a question about avoiding the things it complains about.
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To put it bluntly, don't hide the problem by casting and other
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obfuscating practices, solve the problem.
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.Sh INDENTATION AND STYLE
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Believe it or not, there actually exists a guide for indentation and style.
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It isn't generally applied though.
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.Pp
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We would appreciate if people would pay attention to it, and at least not
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violate it blatantly.
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.Pp
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We don't mind it too badly if you have your own style, but please make
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sure we can read it too.
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.Pp
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Please take time to read
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.Xr style 9
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for more information.
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.Sh NAMING THINGS
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Some general rules exist:
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.Bl -enum
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.It
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If a function is meant as a debugging aid in DDB, it should be enclosed
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in
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.Bd -literal -offset indent
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#ifdef DDB
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#endif /* DDB */
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.Ed
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And the name of the procedure should start with the prefix
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.Li DDB_
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to clearly identify the procedure as a debugger routine.
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.El
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.Sh SCOPE OF SYMBOLS
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It is important to carefully consider the scope of symbols in the kernel.
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The default is to make everything static, unless some reason requires
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the opposite.
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.Pp
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There are several reasons for this policy,
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the main one is that the kernel is one monolithic name-space,
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and pollution is not a good idea here either.
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.Pp
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For device drivers and other modules that don't add new internal interfaces
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to the kernel, the entire source should be in one file if possible.
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That way all symbols can be made static.
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.Pp
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If for some reason a module is split over multiple source files, then try
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to split the module along some major fault-line and consider using the
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number of global symbols as your guide.
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The fewer the better.
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.Sh SEE ALSO
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.Xr style 9
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.Sh HISTORY
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The
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.Nm intro
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section manual page appeared in
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.Fx 2.2 .
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