Re: AC_PROG_CC_* shouldn't append multiple options

[Adrian Bunk]

On Fri, Sep 21, 2012 at 11:18:03AM +0300, Andrew W. Nosenko wrote:
> On Fri, Sep 21, 2012 at 8:20 AM, Paul Eggert <address@hidden> wrote:
> > Yup, macros that invoke AC_PROG_CC_C89 and AC_PROG_CC_C99
> > are trouble.  They're trouble now, and they'll continue to
> > be trouble.  It's not clear how to fix this, other than
> > to advise people to avoid those macros, which the patch
> > does in the manual.
> >
> 
> OK.  Assuming that AC_PROG_CC_C99 deprecated and then removed, how I
> supposed to express "give me c99 or higher compiler or raise error if
> there only c89 or lower compiler found"?  In another words: How can I
> set the _lower_ bound of C standard support, after that configure
> should stop trying and just raises an error?

The problem here are the exact semantics of "c99 or higher compiler".

Take gcc as an example:
- in it's default (non-strict) C89 mode it supports some C99
  features like "long long int"
- no version of gcc so far supports C99 completely [1]

What exactly are your usecases where you need to know the mode of the 
compiler, and not whether some specific C99 features are supported?

cu
Adrian

[1] http://gcc.gnu.org/gcc-4.7/c99status.html

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