Re: Add PostgreSQL home page to --help output

> On 12 Feb 2020, at 11:54, Peter Eisentraut <peter(dot)eisentraut(at)2ndquadrant(dot)com> wrote:
>
> On 2020-02-11 10:34, Daniel Gustafsson wrote:
>> Pardon my weak autoconf-skills, what does the inverted brackets (]foo[ as
>> opposed to [foo]) do in the below?
>> -Please also contact<pgsql-bugs(at)lists(dot)postgresql(dot)org> to see about
>> +Please also contact <]AC_PACKAGE_BUGREPORT[> to see about
>
> AC_PACKAGE_BUGREPORT is an Autoconf macro, set up by AC_INIT. The call above is in the context of
>
> AC_MSG_ERROR([[ ... text ... ]])
>
> The brackets are quote characters that prevent accidentally expanding a token in the text as a macro. So in order to get AC_PACKAGE_BUGREPORT expanded, we need to undo one level of quoting.
>
> See also <https://www.gnu.org/savannah-checkouts/gnu/autoconf/manual/autoconf-2.69/html_node/M4-Quotation.html#M4-Quotation> for more information.

Aha, that's what I was looking for in the docs but didn't find. Thanks for
sharing!

cheers ./daniel