Re: Add PostgreSQL home page to --help output

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.

--
Peter Eisentraut http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services