[CMake] Linking problem

[Renaud Detry]

On 07 Nov 2007, at 11:04, Salvatore Iovene wrote:

> On 11/7/07, Renaud Detry <renaudjdetry at airpost.net> wrote:
>>
>> On 07 Nov 2007, at 09:59, Salvatore Iovene wrote:
>>
>>> On 11/7/07, Brandon Van Every <bvanevery at gmail.com> wrote:
>>>> On Nov 7, 2007 2:12 AM, Salvatore Iovene
>>>> <salvatore.iovene+cmake at googlemail.com> wrote:
>>>>> Hi,
>>>>> I'm not 100% sure this is really a CMake related question, but  
>>>>> I'll
>>>>> fire it up anyway:
>>>>>
>>>>> I'm building a series of static libraries, name them liba.a,  
>>>>> libb.a
>>>>> and libc.a, and linking them into a shared library libfoo.so.
>>>>>
>>>>> Then I'm building libx.a liby.a and libz.a and linking them  
>>>>> into the
>>>>> shared libbar.so.
>>>>>
>>>>> Then I have an executable whatever.exe that's linked to to  
>>>>> libfoo.so
>>>>> and libbar.so. The linking of the executable fails complaining of
>>>>> certain missing simbols. Some symbols from liba.a are missing in
>>>>> libbar.so.
>>
>> Let's say that there's a symbol S in liba.a, that S is the only  
>> symbol
>> in its object, and that S is not used by libfoo. In Darwin, S will  
>> not
>> be included in libfoo, and the result you get is expectable. I don't
>> know if this simple explanation translates to Linux.
>
> I don't know either, but that seems to be the case. Any ideas on  
> how to fix it?

IMHO, you shouldn't use symbols from liba in libbar if libbar doesn't
link against liba.

I think you could do either of

1.- make all your static libs dynamic, and link libbar against liba if
     libbar uses symbols from liba.

2.- link neither libfoo nor libbar to liba, but link whatever.exe to
     liba. This will require an extra flag about undefined symbols
     under Darwin, but I don't think ld will complain under Linux.

Option (1) seems far nicer to me.

Hope this helps.
Renaud.