Re: using templates in shared library

[mrs at wrs dot com (Mike Stump)]

> From: Kasper Peeters <K.Peeters@damtp.cam.ac.uk>
> Date: Wed, 9 Dec 1998 19:27:39 +0000 (GMT)

I agree with your frustration...  We need better docs for this stuff.

> Unless I misunderstood your procedure, this also doesn't work. Let
> me state my problem again: I am building _two_ shared libraries and
> _no_ executables. Library 1 uses vector<int> and so does library
> 2. When I build library 1, the default egcs options will result in
> vector<int> being instantiated in library 1. Good. Then I build
> library 2 and during the link phase, I tell it to link dynamically
> to library 1.

> It should be trivial for the linker to figure out that library 1
> already has vector<int>. I want it to drop the instantiation of
> vector<int> from library 2. 

> The -frepo only seems to work if I have an executable too. I could
> make a trivial demo that uses everything in library 1 and 2, but that
> makes the compiler recompile the demo, not the library. 

Assume we have the structure:

       lib1: lib1a.cc lib1b.cc
       lib2: lib2a.cc lib2b.cc lib1.so
       app: app.cc lib1.so lib2.so

You:
	gcc -frepo -c lib1a.cc
	gcc -frepo -c lib1b.cc
	-gcc -frepo -o delete_me lib1a.o lib1b.o
	gcc -shared -o lib1.so lib1a.o lib1b.o

	gcc -frepo -c lib2a.cc
	gcc -frepo -c lib2b.cc
	-gcc -frepo -o delete_me lib2a.o lib2b.o lib1.so
	gcc -shared -o lib2.so lib2a.o lib2b.o

Now, you can try that or let us know if it doesn't work and why.

For the app, one can use default compile or if one wants, one can use
-frepo.

	gcc -o app app.cc lib2.so lib1.so
or
	gcc -frepo -c app.cc
	gcc -frepo -o app app.o lib2.so lib1.so

I think this should work.