Re: usage of ac_check_header

[Joao Miguel Ferreira]

On Wed, 2007-07-25 at 20:55 +0200, Ralf Wildenhues wrote:
> Hello Joao,

Hello Ralph,

thx for the insight.... I really appreciate the great support I've been
getting on this list ever since some weeks ago I started working with
Autotools...

thx a lot everybody

joao


> 
> A couple of notes to the configure.ac you posted:
> 
> * Joao Miguel Ferreira wrote on Tue, Jul 24, 2007 at 11:44:28AM CEST:
> > AC_INIT([libbabel],[0.4])
> [...]
> 
> > #we need libtool; we need shared libraries;
> > AM_PROG_LIBTOOL
> > AC_PROG_LIBTOOL
> > AC_ENABLE_SHARED
> 
> AM_PROG_LIBTOOL and AC_PROG_LIBTOOL are synonyms, so you can delete
> AM_PROG_LIBTOOL.  Moreover, AC_ENABLE_SHARED needs to go before
> AC_PROG_LIBTOOL.
> 
> > #check for STDC headers in the system
> [...]
> 
> > XTRAINCPATHS="-I/usr/include/libxml2/"
> > CFLAGS="$CFLAGS $XTRAINCPATHS"
> > CPPFLAGS="$CPPFLAGS $XTRAINCPATHS"
> > #in fact these settings will end up in the Makefile
> > #but they first allow for ./configure to find the libxml/xpath header
> > #If libmxl/*.h were located at /usr/include/ none of this would be
> > needed, would it ?! No. jmf.
> 
> Why don't you just let the user pass these flags?  Anyway, Keith
> addressed this already.

Yes,. That's right.... I was not aware of that.... I am now. thx.

> 
> > #set some sanity flags... well... some compilers don't know them... "gcc
> > sweet gcc"
> > # additionally -Werror would be too optimistic, wouldn't it ?!...
> > CFLAGS="$CFLAGS -Wshadow -Wunused -Wall -Werror"
> [...]
> 
> I'd add the warning flags only if using GCC:
>   if test "$GCC" = yes; then
>     CFLAGS="$CFLAGS -Wshadow -Wunused -Wall -Werror"
>   fi
> 
> Other compilers will likely not understand them at all. 

I already tried on HPUX/aCC and it doesn't .

>  FWIW, -Werror
> is often too optimistic for portable code.
> 
> Hope that helps.
> 
> Cheers,
> Ralf