Problems with shared library (-fPIC) and tango

[e-t172]

Marius Muja a écrit :
> I'm working on a project that needs to be compiled both as a standalone 
> executable and (part of it) as a shared library. It's been working like 
> that on 32 bit machines without any problems, but now I need to compile 
> it on a 64 bit machine (to be able to access more the 3GB of memory).
> 
> When I tried to build the project on the 64 bit machine I was unable to 
> build the shared library because of the following error:
> 
> libgphobos.a(ti_AC.o): relocation R_X86_64_32 against 
> `_D17TypeInfo_C6Object6__initZ' can not be used when making a shared 
> object; recompile with -fPIC

You can build a D shared library without including Tango in it (there 
will be undefined references in the shared library, which will be 
resolved when Tango is linked with the main executable).

If you're using GDC, use the -nophoboslib switch when creating your 
shared library to avoid linking to Tango.

Some problems can occur, though. If you happen to modify your shared 
library in such a way that the library makes use of a Tango symbol it 
didn't use before, it won't work unless you relink your executable to 
include the new symbol. That kind of defeats the whole purpose of having 
shared libraries. Of course, one could include all Tango symbols in the 
executable to solve the problem, but then you will end with a huge 
executable because all Tango will be included in it.