On 12/12/18 3:13 PM, Roman Bolshakov wrote:
@@ -845,7 +853,10 @@ sc_prohibit_always-defined_macros:
case $$(echo all: | grep -l -f - Makefile) in Makefile);; *) \
echo '$(ME): skipping $@: you lack GNU grep' 1>&2; exit 0;; \
esac; \
- $(def_sym_regex) | grep -E -f - $$($(VC_LIST_EXCEPT)) \
+ sym_regexes=$$(mktemp); \
Are we guaranteed that 'mktemp' is portably present on all developer's
machines?
That's a good question. It's not present on Solaris 9. What platforms
gnulib should cover?
+ $(def_sym_regex) > $$sym_regexes; \
+ $(VC_LIST_EXCEPT) | xargs \
+ grep -E -f $$sym_regexes /dev/null \
&& { echo '$(ME): define the above via some gnulib .h file' \
1>&2; exit 1; } || :; \
Even worse, you aren't cleaning up your temporary file. This conversion
needs to be rewritten in a better manner. I suggest:
$(VC_LIST_EXCEPT) | xargs sh -c \
'$(def_sym_regex) | grep -E -f - "$$@"' dummy /dev/null
which uses 'sh' as an intermediary to let you still feed $(def_sym_regex) as
the stdin to the grep process (the dummy argument supplies $0 to sh, then
the /dev/null is the usual placeholder to ensure grep sees more than one
file at a time to avoid its output changing styles).
Ok, I was struggling to find a portable solution. Thank you for
proposing this one (and explaining it). The macro can't be expanded
without breaking shell parser though. I don't know... the approach with
mktemp is more readable but I'm not sure if that's what we want to use
because of portability concerns.
My initial problem with mktemp is its portability, the bigger problem is
that you don't clean the temp file up. But rewriting to an alternative
form that avoids the temp file means we don't have to even think about
mktemp problems.
So, all that remains is your comment about $(def_sym_regex) being parsed
by sh. And I see what you mean: what I wrote won't work, because make
would expand it to something like this (well, there are more levels of
make variables substituted before the actual shell command, but this is
enough expansion to show the problem):
$(VC_LIST) | $(SED) 's|^$(_dot_escaped_srcdir)/||' \
| if test -f $(srcdir)/.x-$@; then grep -vEf $(srcdir)/.x-$@; \
else grep -Ev -e "$${VC_LIST_EXCEPT_DEFAULT-ChangeLog}"; fi \
| grep -Ev -e '($(VC_LIST_ALWAYS_EXCLUDE_REGEX)|$(_sc_excl))' \
$(_prepend_srcdir_prefix) \
xargs -sh -c ' \
gen_h=$(gl_generated_headers_); \
(cd $(gnulib_dir)/lib; \
for f in *.in.h $(gl_other_headers_); do \
test -f $$f \
&& perl -lne '$(gl_extract_significant_defines_)' $$f;\
done; \
) | sort -u \
| $(SED) 's/^/^ *# *(define|undef) */;s/$$/\\>/ \
| grep -E -f - "$$@"' dummy /dev/null
where the embedded ' in the expansion of $(def_sym_regex) don't do well
through a second round of sh parsing. Obviously, I didn't test things,
and was acting more like I had a shell variable than a make variable.
But it seems like a shell variable would do the trick (unless you hit
other command line limits?):
regex=`$(def_sym_regex)`; export regex; \
$(VC_LIST_EXCEPT) \
| xargs sh -c 'echo $$regex | grep -E -f - "$$@"' dummy /dev/null
I'll have to rely on you to test it, since I'm not running into the
limits on my machine, but hopefully that helps you with some ideas.
--
Eric Blake, Principal Software Engineer
Red Hat, Inc. +1-919-301-3266
Virtualization: qemu.org | libvirt.org
