Re: checking Mac OS X headers

[Ralf Wildenhues]

Hello Vincent,

* Vincent Torri wrote on Sat, Nov 14, 2009 at 08:20:12PM CET:
> On Sat, 14 Nov 2009, Ralf Wildenhues wrote:
> >>configure:11850: checking whether we are using the GNU Objective C compiler
> >>configure:11869: gcc -c   conftest.m >&5
> >>gcc: error trying to exec 'cc1obj': execvp: No such file or directory
> >>configure:11869: $? = 1
> >
> >Your compiler doesn't speak Objective C.  Solution is to install the
> >respective frontend.
> 
> i don't have it and i don't want to install it. I would like to
> check the Mac OS X header only if an Objective C compiler is
> present, as i have to use an objective c compiler (hance the
> AC_LANG_PUSH in the code). But it seems that the use of m4_ifdef is
> not sufficient.
> 
> do you have an idea of how to do that ?

Besides the answer Peter already gave you, which is probably the right
thing for you, finding out whether the Objective C compiler can compile
and link code should be possible as follows (untested):

  AC_LANG_PUSH([Objective C])
  AC_MSG_CHECKING([whether then Objective C compiler works])
  AC_LINK_IFELSE([AC_LANG_PROGRAM([])],
    [AC_MSG_RESULT([yes])],
    [AC_MSG_RESULT([no])])
  AC_LANG_POP([Objective C])

Similar with AC_RUN_IFELSE if you require a run test (but take care of
the cross-compile scenario in that case).

Cheers,
Ralf