Re: QUERY: Inclusion of header files in kernel header files

[Clemens Ladisch]

Theodore Tso wrote:
> Also, it's highly desirable that as much as possible multiple
> inclusion is fixed up at the same time you add extra #includes into
> header files.   Protecting against multiple inclusion is critical,
> yes, but even with the protection against multiple inclusion, the
> header file has to get parsed a second time, and that slows down
> kernel compiles.

Multiple inclusion of a protected header does not hurt at all; gcc
detects that a header file uses #ifdef/#endif header guards and
automatically ignores any #include for that file if the symbol is
already defined.


Regards,
Clemens
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