1.\" Copyright (c) 1983, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. All advertising materials mentioning features or use of this software 13.\" must display the following acknowledgement: 14.\" This product includes software developed by the University of 15.\" California, Berkeley and its contributors. 16.\" 4. Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" $FreeBSD: src/share/man/man9/intro.9,v 1.10.2.5 2001/08/17 13:08:54 ru Exp $ 33.\" 34.Dd December 13, 1995 35.Dt INTRO 9 36.Os 37.Sh NAME 38.Nm intro 39.Nd "introduction to system kernel interfaces" 40.Sh DESCRIPTION 41This section contains information about the interfaces and 42subroutines in the kernel. 43.Sh PROTOTYPES ANSI-C AND ALL THAT 44Yes please. 45.Pp 46We would like all code to be fully prototyped. 47.Pp 48If your code compiles cleanly with 49.Nm cc 50.Ar -Wall 51we would feel happy about it. 52It is important to understand that this isn't a question of just shutting up 53.Nm cc , 54it is a question about avoiding the things it complains about. 55To put it bluntly, don't hide the problem by casting and other 56obfuscating practices, solve the problem. 57.Sh INDENTATION AND STYLE 58Believe it or not, there actually exists a guide for indentation and style. 59It isn't generally applied though. 60.Pp 61We would appreciate if people would pay attention to it, and at least not 62violate it blatantly. 63.Pp 64We don't mind it too badly if you have your own style, but please make 65sure we can read it too. 66.Pp 67Please take time to read 68.Xr style 9 69for more information. 70.Sh NAMING THINGS 71Some general rules exist: 72.Bl -enum 73.It 74If a function is meant as a debugging aid in DDB, it should be enclosed 75in 76.Bd -literal -offset indent 77#ifdef DDB 78 79#endif /* DDB */ 80.Ed 81.Pp 82And the name of the procedure should start with the prefix 83.Li DDB_ 84to clearly identify the procedure as a debugger routine. 85.El 86.Sh SCOPE OF SYMBOLS 87It is important to carefully consider the scope of symbols in the kernel. 88The default is to make everything static, unless some reason requires 89the opposite. 90.Pp 91There are several reasons for this policy, 92the main one is that the kernel is one monolithic name-space, 93and pollution is not a good idea here either. 94.Pp 95For device drivers and other modules that don't add new internal interfaces 96to the kernel, the entire source should be in one file if possible. 97That way all symbols can be made static. 98.Pp 99If for some reason a module is split over multiple source files, then try 100to split the module along some major fault-line and consider using the 101number of global symbols as your guide. 102The fewer the better. 103.Sh SEE ALSO 104.Xr style 9 105.Sh HISTORY 106The 107.Nm 108section manual page appeared in 109.Fx 2.2 . 110