FreeBSD 6.0 and onwards

[Dag-Erling Smørgrav]

Yuval Levy <freebsd-current at sfina.com> writes:
> A currency converter function is part of a web based application plattform:
> converted_amount = conversion (original_amount, original_currency,
> converted_currency). Then we realized we might also need to format the
> conversion for display. Introduce a fourth argument, a bolean
> (format/non-format). The new function was converted_amount = conversion
> (original_amount, original_currency, converted_currency, format). By testing
> if the fourth argument exists and defaulting to the original behaviour if it
> does not we upgraded without breaking the applications.

You were using a language (Perl, PHP, Java, whatever) which allows you
to do that.  C does not (at least not easily).  We can and do provide
backward compatibility for the kernel-userland interface (system
calls), but we can't easily provide it for internal kernel APIs.

DES
-- 
Dag-Erling Smørgrav - des at des.no