— introduction to system kernel
This section contains information about the interfaces and subroutines in the
PROTOTYPES ANSI-C AND ALL
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.
INDENTATION AND STYLE¶
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
And the name of the procedure should start with the prefix
#endif /* DDB */
DDB_ to clearly identify the procedure as a
SCOPE OF SYMBOLS¶
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
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.
section manual page appeared in