Re: AC_LANG_PROGRAM(C): function 'main' without prototype

[Stepan Kasal]

Hello,

On Tue, Jun 24, 2008 at 08:14:44PM +0200, Nico R. wrote:
> AC_LANG_PROGRAM(C) in c.m4 from autoconf:
> Shouldn’t the line
>   main ()
> be
>   main (void)
> instead?

I admit I'm not sure about this.  The change would immediately break
K&R compilers but they are no longer in the target set anyway.
Let's wait for comments from those who know better. ;-)

> If CFLAGS contains '-Werror’

Well, the configure collects literally bits of information about the
platform.  The bit is 0 or 1, depending on whether the compilation
(link) failed or not.  Using -Werror may skew some results.

If these mis-detected bit of information break the build, we get a bug
report, like in this case.  But what if the mis-detected bits do not
prevent a build?  The build just fails to use a feature which should
otherwise be used, so the build disables that feature or reimplements
it internally.

Generally, while -Werror during "make" makes you more safe, -Werror
at configure time exposes you to extra risk.

Perhaps we should do something about it.  Perhaps ./configure should
detect -Werror in CFLAGS (and other *FLAGS) and bail out with an
error message.

Wdyt?

Stepan Kasal