Re: Is C++ used in life-critical systems?
On Dec 15, 9:47 pm, Michael Doubez <michael.dou...@free.fr> wrote:
On 15 d=E9c, 22:14, "Marc" <xmarc...@spot.net> wrote:
[...]
C++ Question:
Is C++ used in life-critical systems? Expound please.
Yes. It does. B. Stroustrup page give references although it doesn't
extend to which part of a critical system it is used.
For the people I've met of the sector, it is however often not their
first choice. IMHO it is partly cultural but there is also some kind
of distrust toward things that get too much out of control and c++
does delegate a lot of mechanisms to the compiler (the so called under
the hood mechanisms).
It's not just cultural. There are two mostly valid arguments
about C++: the language has too much undefined behavior (which
reduces the trust you can place in testing), and the language is
too complicated (which reduces the trust you can place in the
compiler).
Like all things, they have to be weighed against other aspects:
if you are choosing between Ada and C++, for example, the fact
that the C++ compiler has been more intensely used (and thus
more tested) may outweigh the additional complexity; the fact
that you have to write less code may mean increased trust
(supposing that you trust the compiler more than you trust your
programmers:-)).
Non-C++-specific Question:
Recognizing that higher-level supervision (by other systems) is surely =
a
common design in critical systems, thatwithstanding, how does any one
specific program handle detected bugs (the program itself detected a bu=
g)
at runtime in released software?
Basic one is log at point of failure. At least, if there is crash, it
is nice to be able to locate the bug/problem in order to fix it (or
get out of sue suite) without waiting for the next crash.
Most embedded systems don't have any support for logging. It's
not unusual, however, to "checkpoint" code, placing information
about recent operations in some sort of non-volatile fixed
length circular buffer. Whether you dare do even this once
you've found a software error, I don't know---most of the time,
I think it would be avoided in favor of terminating more
quickly.
--
James Kanze