On 2024-07-18 09:40, Zack Weinberg wrote:
> On Thu, Jul 18, 2024, at 5:09 AM, Tijl Coosemans wrote:
>> Automake 1.17 produces a warning for the use of \# ...
>
> For reference, the construct in question is
>
> subst = sed \
> -e 's|@PACKAGE_VERSION[@]|$(PACKAGE_VERSION)|g' \
> -e '1 s|^\#\!.*perl$$|\#\!$(PERL)|g' \
> -e 's|@localstatedir[@]|$(localstatedir)|g' \
> [etc]
[...]
> I could be wrong about this, but I don't think any implementation of Make
> pays _any_ attention to shell quotation in commands. Therefore, no, this
> is not portable.
Note that there is only any problem at all because the # characters are
used in a make variable assignment. If it was written literally into a
rule instead, for example:
substitute:
sed -e '1s|^#!.*perl$$|#!$(PERL)|g' ...
there is no portability problem, as # does not introduce a make comment
when it appears within the commands of a rule.
If the only reason for using a make variable is just to reduce typing
(because it's used in more than one rule) one simple option is to use
a configure-time substitution instead (totally untested):
configure.ac:
AC_SUBST([blargh], ['sed -e '\''1s|^#!.*perl|#!$(PERL)|'\'])
AM_SUBST_NOTMAKE([blargh])
Makefile.am:
substitute:
@blargh@ ...
Cheers,
Nick
