The Autoconf manual states that no space should occur before the opening
parenthesis in a macro call:
When calling macros that take arguments, there must not be any white
space between the macro name and the open parenthesis.
AC_INIT ([oops], [1.0]) # incorrect
AC_INIT([hello], [1.0]) # good
However, the documentation of all the macros has such a space:
Every ‘configure’ script must call ‘AC_INIT’ before doing anything else
that produces output. Calls to silent macros, such as ‘AC_DEFUN’, may
also occur prior to ‘AC_INIT’, although these are generally used via
‘aclocal.m4’, since that is implicitly included before the start of
‘configure.ac’. The only other required macro is ‘AC_OUTPUT’ (*note
Output::).
-- Macro: AC_INIT (PACKAGE, VERSION, [BUG-REPORT], [TARNAME], [URL])
Process any command-line arguments and perform initialization and
verification.
I checked this with the Autoconf Info manual downloaded from
https://www.gnu.org/software/autoconf/.
Arguably, it should look like this instead:
-- Macro: AC_INIT(PACKAGE, VERSION, [BUG-REPORT], [TARNAME], [URL])
This was due to the output of Texinfo for the definition commands that
are used to document these macros. However, since Texinfo 7.0, you can
give a command in the Texinfo source which causes no such space to be output.
You can add this to autoconf.texi with a change like the following:
--- autoconf.texi 2025-07-18 16:20:44.248495314 +0100
+++ autoconf.texi-2 2025-07-18 16:20:23.669894776 +0100
@@ -7,6 +7,7 @@
@documentencoding UTF-8
@set txicodequoteundirected
@set txicodequotebacktick
+@set txidefnamenospace
@setchapternewpage odd
@finalout
This is backwards-compatible with older versions of Texinfo, which will
ignore this flag.
https://www.gnu.org/software/texinfo/manual/texinfo/html_node/No-Space-After-Definition-Name.html
The only downside is that the macro name stands out less in the documentation
so it may be very slightly harder to find a macro when scrolling through
the documentation. However, I think it's useful to avoid misleading beginners
to Autoconf.
