Re: [Torcs-devel] OS X linkage problems

[Brent B. <bre...@gm...>]

Some observations on the linkage issue with plib.

The issue occurs with the ssggraph module, and the grVtxTable subclass
of plib's ssgVtxTable. One of the ssgVtxTable constructors is:
ssgVtxTable(GLenum type, ssgVertexArray* va, ssgNormalArray* na,
ssgTexCoordArray* ta, ssgColourArray* ca)

GLenum is defined as "unsigned int" in GL/gl.h, so the output from the
plib framework's dylib (or a local static lib) has the signature:
    $ nm -g plib.framework/Versions/A/plib  | c++filt | grep
'ssgVtxTable::ssgVtxTable'
    00075972 T ssgVtxTable::ssgVtxTable(unsigned int,  ...as above...)
    0000234e T ssgVtxTable::ssgVtxTable(unsigned int, .....)
# <- output from my /usr/local/lib/libplibssg.a

I wrote a small test code based on the grVtxTable subclassing that
replicates this problem. The main() simply instantiates a grVtxTable,
which in turn invokes the above constructor. In tinkering with this
test, I found when it works and when it doesn't link.

If I compile the code manually, but link against *static* libraries,
the link works fine. The test source object file is looking for:
    nm -g libvtx.o | c++filt | grep 'ssgVtxTable::ssgVtxTable'
             U ssgVtxTable::ssgVtxTable(unsigned int, ...as above...)
and the linker finds it in the static libraries.

If I compile the test code to make a .so (as Torcs does), then the
compiler is attempting to find the signature with "unsigned long":
    $ nm -g libvtx.o | c++filt | grep 'ssgVtxTable::ssgVtxTable'
             U ssgVtxTable::ssgVtxTable(unsigned long, ...as above...)
and the linker does not find this in the dynamic library (plib framework).

Static linking finds the "unsigned int" version OK, and dynamic
linking is looking for "unsigned long". I've looked through project
settings and compiler options, but I didn't find anything relevant.

Any ideas?

thanks,
-Brent