dlopen of several lib

[Anthony Catel]

I have a program which load two lib (A and B).
In A i want to use some symbols of B. The problem is that lib A is
loaded before B and I get :
" undefined symbol: foo".

What is the best way to solve this kind of case ?
Load B in all lib where I use it ?

What pattern is generaly used for plugins system with dependency between
them ?

Thanks

 

[Antoninus Twink]

I have a program which load two lib (A and B).
In A i want to use some symbols of B. The problem is that lib A is
loaded before B and I get :
" undefined symbol: foo".

What is the best way to solve this kind of case ?
Load B in all lib where I use it ?

The best way is, when you're linking A, to link against B. This will
record B as a dependency of A, and when you dlopen() the library A,
you'll automatically load its dependent B too (and so on recursively, if
necessary).

Of course, you should make sure that you're exporting all symbols
properly (e.g. by giving the -rdynamic option to gcc).

 

[Anthony Catel]

Thanks for your answer.

So, I can compile B like that :

gcc -Wl,-soname,libA.so.1 -rdynamic -o lib/libA.so libA.c


and A like that ? :

gcc -Wl,-soname,libB.so.1 -o lib/libB.so libB.c -L./lib -lA


Thanks

Antoninus Twink a écrit :

 

[Anthony Catel]

(I forgot -shared and -fPIC)

Anthony Catel a écrit :

 

[Keith Thompson]

I have a program which load two lib (A and B).
In A i want to use some symbols of B. The problem is that lib A is
loaded before B and I get :
" undefined symbol: foo".

What is the best way to solve this kind of case ?
Load B in all lib where I use it ?

What pattern is generaly used for plugins system with dependency between
them ?

This isn't something that's specified by the lnaguage. You're likely
to get better answers in a newsgroup that deals with your system;
since you mentioned dlopen in the subject header, that's probably
comp.unix.programmer.

 

[Stephen Sprunk]

Thanks for your answer.

So, I can compile B like that :

gcc -Wl,-soname,libA.so.1 -rdynamic -o lib/libA.so libA.c


and A like that ? :

gcc -Wl,-soname,libB.so.1 -o lib/libB.so libB.c -L./lib -lA

Since this is all gcc-specific, you will get better answers over on
gnu.gcc.help.

<OT>
The example above appears to link B against A, whereas it sounds like
you need to link A against B, since A needs a symbol that's in B.
</OT>

S

 

[Anthony Catel]

Yes my mistake

Thanks

Stephen Sprunk a écrit :