Re: [jamboost] order of static and dynamic libraries

From: Toon Knapen (toon.knapen_at_[hidden])
Date: 2004-04-28 11:34:25

Rene Rivera wrote:

> Toon Knapen wrote:
> 
> 
>>I have a dynamic library 'bar' that calls MPI routines (or whatever 
>>third party library) that are defined in a static library. Now my 
>>executable 'foo' calls a function defined in 'bar' and also calls MPI 
>>functions.
>>
>> foo.exe ----calls----> bar.so ----calls-----> MPI (mpich.a, pmpich.a)
>> | ^
>> |---------------------------------------------
>>
> In your small example I do have a question... Why do you add the MPI 
> dependency to the foo.exe instead of adding it to the bar.so, which is 
> the one that has the real requirement? Doing that instead would solve 
> the link order problem in this case.
> 

I thought about doing this. This would mean that the mpi functions are 
defined in bar.so as well. So when linking foo.exe with bar.so and 
libmpich.a I was afraid to have multiple defines or blowing up the size 
of the exe. But probably my fear is unjustified since the linker will 
just drop the second (and up) definition of the MPI function. right ?

However this is not a real clean solution IMO because suppose that I 
create bar.so but somebody else uses my bar.so and links foo.exe. Now my 
bar.so contains (part of) the MPI library definitions. If somebody else 
now links with bar.so _and_ links with the MPI libraries installed on 
_his_ machine, he's possibly linking the application with 2 different 
versions of the MPI libaries which might result in strange behaviour.