Re: Plugin support for FreeBSD and OS X

[Ian Lance Taylor <iant at google dot com>]

"Nicholas \"Indy\" Ray" <arelius@gmail.com> writes:

> That would probably work, but then the configure script won't test for
> dlopen functionality, which is required. maybee I should put an
> additional AC_TRY_LINK in the test failure? is there a better way to
> do that then just a wholesale duplication of the macro?

AC_SEARCH_LIBS(dlopen, -ldl, found_dlopen=yes, found_dlopen=no)

This will add -ldl to $LIBS if necessary (i.e., don't reset LIBS) and
set found_dlopen to indicate whether it was found or not.

Ian  

> On Mon, Oct 5, 2009 at 4:22 PM, Ian Lance Taylor <iant@google.com> wrote:
>> "Nicholas \"Indy\" Ray" <arelius@gmail.com> writes:
>>
>>> So are you suggesting that the entire block:
>>>
>>> Â LIBS="$LIBS -ldl"
>>> Â AC_MSG_CHECKING([for -ldl])
>>> Â AC_TRY_LINK(
>>> Â Â [#include <dlfcn.h>],
>>> Â Â [volatile int f = 0; if (f) dlopen ("dummy", 0);],
>>> Â Â [AC_MSG_RESULT([yes]); have_dl=yes],
>>> Â Â [AC_MSG_RESULT([no])])
>>> Â if test x"$have_dl" = x"yes"; then
>>> Â Â pluginlibs="$pluginlibs -ldl"
>>> Â fi
>>>
>>> should be replaced with something based on AC_CHECK_LIB? I'll give that a test!
>>
>> I hadn't looked at that code. ÂThat all looks fine to me, although
>> AC_CHECK_LIB would be simpler.
>>
>> Are you saying that that does not work on FreeBSD? ÂHow does it fail?
>>
>> Wait, I think I see the problem: the code sets LIBS to include -ldl,
>> but fails to reset it if the test fails. ÂProbably all it needs is two
>> new lines:
>>
>> Â if test x"$have_dl" = x"yes"; then
>> Â Â pluginlibs="$pluginlibs -ldl"
>> + Âelse
>> + Â ÂLIBS="$saved_LIBS"
>> Â fi
>>
>> Ian
>>
>>
>>> On Mon, Oct 5, 2009 at 3:38 PM, Ian Lance Taylor <iant@google.com> wrote:
>>>> "Nicholas \"Indy\" Ray" <arelius@gmail.com> writes:
>>>>
>>>>> The problem is that on FreeBSD -ldl is not available or required, the
>>>>> functionality is provided by libc
>>>>
>>>> I think understand that. ÂWhat I am saying is that the configure
>>>> script should test for that property--the fact that -ldl is not
>>>> available or required--rather than test the type of host for which gcc
>>>> is being configured.
>>>>
>>>> Ian
>>>>
>>>>
>>>>> Nicholas "Indy" Ray
>>>>>
>>>>> On Mon, Oct 5, 2009 at 3:05 PM, Ian Lance Taylor <iant@google.com> wrote:
>>>>>> "Nicholas \"Indy\" Ray" <arelius@gmail.com> writes:
>>>>>>
>>>>>>> Indeed, I've sent in a small patch for a warning I got on FreeBSD,
>>>>>>> however I'm not sure how to get autoconf to check the host system,
>>>>>>> I'll examine other locations in the code and see if I can't cobble a
>>>>>>> patch together.
>>>>>>
>>>>>> When possible, a configure script should test for features, not
>>>>>> operating systems. ÂSo, for example, the goal would be not to check
>>>>>> for FreeBSD, but rather to check for the availability of -ldl, which
>>>>>> is typically done using AC_CHECK_LIB.
>>>>>>
>>>>>> Ian
>>>>>>
>>>>
>>