symlink dll (was: Can upset handle more than one prev: tag?)

[Max Bowsher]

Reini Urban wrote:
> Max Bowsher schrieb:
>> Reini Urban wrote:
>>> Max Bowsher schrieb:
>>>> Reini Urban wrote:
>>>>> Shouldn't we then provide a cygperl5_8.dll symlinked to
>>>>> cygperl5_8_5.dll
>>>>> also (in linux fashion), and apps should link against cygperl5_8.dll
>>>>> resp. a more generic libperl.dll.a then?
>>>>> otherwise you'll have to recompile all dependent apps.
>>>>
>>>>
>>>> You are forgetting something. The Windows runtime linker
>>>> (understandably) doesn't understand Cygwin symlinks.
>>>
>>>
>>> But cygwin dlopen does understand symlinks.
>>> And perls dynalinker uses dlopen(cygpath),
>>> not LoadLibrary (fullpath).
>>> All other posix libs also use dlopen() not LoadLibrary().
>>> And the cygwin dlopen() calls fullpath = get_full_path_of_dll(cygpath)
>>> which resolves links.
>>
>> True, but entirely missing the point.
>>
>> cygperlxxx.dll is also used by things doing "gcc -lperl", not dlopen or
>> LoadLibrary.
>
> this search look for libperl.la or libperl.a.
> and the for the .dll.a (by convention) if shared.
>
> but simple path lookup in the .la file reader should resolve softlinks
> also. binutils maintainer??
>
> /lib/libxerxes-c25.dll.a also uses softlinks from libxerces-c.dll.a and
> libxerces.dll.a
>
> /bin/cygdb-41.dll.lnk is a softlink to /bin/cygdb-4.1.dll

Um, really? Not as part of the official package.

> create a /lib/libperl.la
> and symlink /lib/libperl.dll.a to
> /lib/perl5/5.8.5/cygwin-thread-multi-64int/CORE/libperl.dll.a

Once again, mostly true, but entirely missing the point.

Whatever symlink games you play at *link-time* (i.e gcc, binutils), only one 
name can be hardcoded into the final binary, and that file must be a real 
file, not a symlink, because at *run-time* it is a core component of Windows 
which reads the data structures in the PE file, and loads and links the 
DLLs, without any influence from any part of Cygwin.

Max.