Re: accepted by the compiler, rejected by the preprocessor!

[Brendan Cully]

On Friday, 21 March 2003 at 14:21, Paul Eggert wrote:

I've noted some typos in case you want to fix them.

> The next version of Autoconf will have some documentation about this.
> Here's the current draft, written by Akim Demaille, in Texinfo format:
> 
> 
> 
> @node Present But Cannot Be Compiled
> @section Header Present But Cannot Be Compiled
> 
> The most important guideline to bare in mind when checking for
                                  bear
> features is to mock as much as possible the intended use.
                 mimic
> Unfortunately, old versions of @code{AC_CHECK_HEADER} and
> @code{AC_CHECK_HEADERS} failed to follow this idea, and used to call
                                                          called
> the preprocessor, instead of the compiler, to check for headers.  As a
> result, incompatibilities between headers went unnoticed during
> configuration, and maintainers finally had to deal with this issue
> elsewhere.
> 
> Since Autoconf 2.56 both checks are performed, and @code{configure}
  As of
> complains loudly if the compiler and the preprocessor do not agree.
> For the time being the result is that of the preprocessor, so that
                               ^used
> maintainers can adjust their @file{configure.ac}, but in the near
> future, the compiler only will be considered.
         ^only         ----