intro —
introduction to system kernel interfaces
This section contains information about the interfaces and subroutines in the
kernel.
Yes please.
We would like all code to be fully prototyped.
If your code compiles cleanly with
cc
-Wall we would feel happy about it. It is
important to understand that this is not a question of just shutting up
cc, it is a question about avoiding the things it
complains about. To put it bluntly, do not hide the problem by casting and
other obfuscating practices, solve the problem.
Believe it or not, there actually exists a guide for indentation and style. It
is not generally applied though.
We would appreciate if people would pay attention to it, and at least not
violate it blatantly.
We do not mind it too badly if you have your own style, but please make sure we
can read it too.
Please take time to read
style(9) for more
information.
Some general rules exist:
- If a function is meant as a debugging aid in DDB, it
should be enclosed in
#ifdef DDB
#endif /* DDB */
And the name of the procedure should start with the prefix
DDB_ to clearly identify the procedure as a
debugger routine.
It is important to carefully consider the scope of symbols in the kernel. The
default is to make everything static, unless some reason requires the
opposite.
There are several reasons for this policy, the main one is that the kernel is
one monolithic name-space, and pollution is not a good idea here either.
For device drivers and other modules that do not add new internal interfaces to
the kernel, the entire source should be in one file if possible. That way all
symbols can be made static.
If for some reason a module is split over multiple source files, then try to
split the module along some major fault-line and consider using the number of
global symbols as your guide. The fewer the better.
style(9)
The
intro section manual page appeared in
FreeBSD 2.2.