Re: What is "ac_nonexistent.h"?

[Ralf Wildenhues]

Hello, and sorry for any name mangling,

* Eric Blake wrote on Mon, Mar 07, 2011 at 03:44:59PM CET:
> On 03/07/2011 04:42 AM, ������ wrote:
> > "error: ac_nonexistent.h, no such file or directory."
> > ...
> > "Compilation terminated."
> > Fortunately that is the only error which appeared several times in the 
> > config.log file.
> 
> That's a _good_ thing.  We _expect_ that compilation error, to prove
> that we are correctly detecting how your compiler detects and rejects
> broken source code that refers to a non-existent header (knowing how the
> compiler detects missing headers is essential for later tests of
> AC_CHECK_HEADERS to see which headers are present).
> 
> Not all failed compilations are bugs.

Maybe AC_*_IFELSE should allow to denote the expected outcome, in
order to put only the unexpected outcome verbosely in config.log.

Cheers,
Ralf