Paul Smith wrote in
<898afb17671ea69f18ae7a4ed22a57aa35eb87e0.ca...@gnu.org>:
|On Sat, 2020-12-19 at 00:04 +0100, Steffen Nurpmeso wrote:
|> While finding a way to truly detect whether being run by BSD make
|> (which cannot supervise a shell script that turns on "set -m" to
|> monitors its childs) i stumbled upon the fact that
|>
|> $ make -p
|>
|> exits 2.
|
|Yes. The manual says specifically:
|
|> Print the data base (rules and variable values) that results from
|> reading the makefiles; then EXECUTE AS USUAL OR AS OTHERWISE
|> SPECIFIED.
|
|(emphasis added). If you examine the output you'll see that you got an
|error:
|
| make: *** No targets specified and no makefile found. Stop.
|
|and the manual says:
|
|> 2
|> The exit status is two if make encounters any errors. It will print
|> messages describing the particular errors.
|
|so this is as expected.
Oh. I see, sorry for the noise then!
|I guess there is some issue with the documentation here since the error
|message is actually shown before the database is printed while the
|documentation implies that the database will be printed first.
|
|> Even if i follow the manual advice
|>
|> $ make -p -f /dev/null
|>
|> i get complains (bad manual advice!),
|
|I don't see why it's bad advice. The advice doesn't say that it will
|run with a 0 exit code, it just says that if you want to see the
|default targets, without any targets defined by your makefile, you can
|try using "-f /dev/null".
|
|> $ echo all: > y.mk; make -p -f y.mk
|
|You don't need to make a file: you can do something like this:
|
| $ echo 'all:;' | make -p -f-
Yes, thanks. But no, the test is solely to find out whether we
run running BSD make, which has no -p (yet, but he sounds as if
that remains), but he says i should watch out for .PARSEDIR, so
i end up doing
case "${JOBMON}" in
[yY]*)
# BSD make cannot monitor shells which monitor
i=
( ${MAKE} -p ) >/dev/null 2>&1
if [ ${?} -ne 0 ]; then
${cat} > .t.mk.mon <<'_EOT'
all:
@printf ''
ifdef .PARSEDIR
.if defined(.PARSEDIR)
@echo yes
.endif
endif
_EOT
i=`${MAKE} -f .t.mk.mon 2>/dev/null`
if [ ${?} -ne 0 ] || [ -n "${i}" ]; then
i="${MAKE} cannot supervise sh(1)ells with"
fi
fi
if [ -z "${i}" ] && (set -m >/dev/null 2>&1); then
JOBMON=y
else
[ -z "${i}" ] && i="${SHELL} does not support"
echo >&2 ${i}" \"set -m[onitor]\"!"
echo >&2 'Failing (hanging) tests could leave stale processes around!'
JOBMON=
fi
;;
*)
JOBMON=
;;
esac
Maybe i am too tired and fail to see a better way, the above works
as desired for GNU make, Schily make, SunOS 5.9 and 5.10 make, and
BSD make fails for -p and the ifdef, and shall it ever support the
compatibility for ifdef then it will still work (until anyone
implements .PARSEDIR).
Thank you!
And a nice weekend i wish from Germany,
--steffen
|
|Der Kragenbaer, The moon bear,
|der holt sich munter he cheerfully and one by one
|einen nach dem anderen runter wa.ks himself off
|(By Robert Gernhardt)
