Re: AC_TRY_RUN and cross-compiling (was: Re: ORBit 0.5.8 Cross-Compile problems...)

[Ossama Othman]

Hi Dan,

On Mon, Apr 01, 2002 at 11:38:27AM -0800, Dan Kegel wrote:
> Ossama Othman wrote:
> > I have to agree with Paul.  Sometimes it's just not possible to rely
> > on compile/link-time tests alone.
> 
> That's ok if three things hold:
> 1. configure.in authors avoid gratuitous use of AC_TRY_RUN.

That should certainly be feasible unless there are some bizarre
platforms out there.  In any case, this shouldn't be a problem if
developers use a reasonable "action-if-cross-compiling" argument for
AC_TRY_RUN, such as a compile/link-time test.

> 2. All autoconf macros that use AC_TRY_RUN allow overriding the
>    test via environment variables.  (This comes for free if you
>    use the cache, I think.)  configure.in authors who write
>    custom macros may need education on this.

I would tell them to RTFM.  :-)

> 3. AC_TRY_RUN lets the user specify how to run code on the target,
>    e.g. with a --with-target-run=foo.sh option, where foo.sh is
>    a script that runs the given command remotely, e.g. via ssh.
>    (By default, configure would assume you can't run code on the target
>    when cross-compiling, just like now.)

BTW, did terminology change?  I thought that "target" was only used
for tool chains (e.g. compiler, linker, etc).  Shouldn't the bulk of
applications be using "host."  For example, "./configure
--build=... --host=...".  If terminology has changed then someone
needs to update the autoconf manual on the GNU autoconf web site.

-Ossama
-- 
Ossama Othman <address@hidden>
Distributed Object Computing Laboratory, Univ. of California at Irvine
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