Re: Obsoleting LT_SCOPE

[Gary V. Vaughan]

Hi Peter,

On 25 Oct 2011, at 18:12, Peter Rosin wrote:
> Gary V. Vaughan skrev 2011-10-25 12:51:
>> I note that no other GNU projects that I'm aware of jump through all the
>> __declspec hoops that the libltdl API tries to provide through LT_SCOPE.
>> Is any of this stuff still required on any non-museum Windows compiler
>> that would break if I removed it?
>> 
>> Here's what I'm proposing to do for the upcoming libtool alpha release:
>> 
>>  1. Remove all traces of LT_SCOPE, and just use plain 'extern' in
>>     public header files.
>>  2. Remove the code for setting and passing LTDL_DLL_IMPORT.
>>  3. I can then safely eliminate $prefix/include/libltdl/lt_system.h,
>>     and simplify the public headers for libltdl considerably.
>> 
>> Do you forsee any issues on Windows with my doing that?
>> 
>> I'm almost certain that modern gcc and hence cygwin and variants will
>> continue to work correctly without LT_SCOPE, LTDL_DLL_IMPORT and friends,
>> but I have no clue whether vendor compilers that currently work (or at
>> least are supported and supposed to work) with the current release are
>> relying on LT_SCOPE magic from libltdl.
> 
> I'm fairly certain that removing LT_SCOPE wholesale would break Libtool
> in one way or the other for Microsoft Visual C. Please don't do it
> without checking the effects on the testsuite first.
> 
> I can check if you provide a patch.

Awesome, thanks.

I put up a set of tarballs from a make distcheck of the 2.4.2 release with
a minimal patch that simply forces LT_SCOPE to always be extern.  You can get
them here:

  http://vaughan.pe/libtool/libtool-2.4.2-no-lt-scope.tar.gz
  http://vaughan.pe/libtool/libtool-2.4.2-no-lt-scope.tar.xz

Obviously they passed a full distcheck on my machine, and I'm quietly hoping
there'll be no regressions on your machines compared to the raw 2.4.2
release I put out recently.  If so, that covers point 1 of my original post,
and I can seriously tidy up the installed files from libltdl and start
thinking more about point 2 as well.

Let me know how you get on.

Cheers,
-- 
Gary V. Vaughan (gary AT gnu DOT org)