Why does compiling a shared object with GCC always result in undefined references to main?

Question

I'm running Solaris, so it's possible that this is specific to running GCC on Solaris. If I use GCC to generate a shared object, and then run nm on it to see undefined symbols, there will always be a reference to main:

[624]     |         0|       0|NOTY |GLOB |0    |UNDEF  |main

If I manually generate the same shared object using ld, the reference to main doesn't exist. If I run nm on the system libraries in /usr/lib, none of them appear to have references to main. Only shared libraries I compile myself with GCC.

Apps compiled against these shared libraries work fine and without errors. But I still don't understand why the reference to main is there in the first place. Any clues?

Answer 1

You forgot the -shared option in your gcc link command line.

EDIT: and you forgot -fPIC option on your compile command line (which is causing all the relocation errors at link time).

If you still get relocation errors with -fPIC on all compile lines, then you should rebuild all the archive libraries which you link in (libtoast_datetime, libtoast_assert, etc.) with -fPIC as well.