Re: [RFC PATCH 2/3] docs: make the docs for MISRA C:2012 Dir 4.1 visible to ECLAIR

[Anthony PERARD <anthony.perard@xxxxxxxxxx>]

On Tue, Aug 22, 2023 at 12:10:28PM +0200, Jan Beulich wrote:
> On 22.08.2023 10:27, Nicola Vetrini wrote:
> >>> +C-runtime-failures.c: C-runtime-failures.rst
> >>> +# sed is used in place of cat to prevent occurrences of '*/'
> >>> +# in the .rst from breaking the compilation
> >>> + ( \
> >>> +   echo "$${MISRA_HEADER}"; \
> >>> +   sed -e 's|*/|*//*|' $<; \
> >>> +   echo "$${MISRA_FOOTER}" \
> >>> + ) > $@
> >>
> >> The rule of thumb is to generate into a temporary file (then you also
> >> don't need to wrap everything in parentheses [or braces]), and then
> >> use mv to produce the final output. This escapes anomalies with failed
> >> or interrupted commands.
> >>
> > 
> > I do see your point for temporary files, though wrapping commands with 
> > parentheses is a
> > fairly common pattern in Xen Makefiles afaict.
> 
> Now I'm curious: Grepping for ') >' underneath xen/ I couldn't find a
> single instance in any makefile. (I'm not going to exclude there are a
> few uses, but then likely not merely to combine multiple commands'
> output.)

Maybe using `{ } > out` might be better that using `( ) > out`. I think
it would result in one less fork of the shell, without changing the
resulting file, so always good to take.

You should add also `set -e` at the beginning, to take care of the `sed`
command failing.

Or just use a temporary file.


-- 
Anthony PERARD