pre_load_libraries

I am trying to create an initialisation function that is called using
the preload_libraries option.

The purpose of this is to set up shared memory for Veil, independant of
postgres' own shared memory. Simple init functions work fine, but as
soon as I place calls to ShemAlloc, or LWLockAssign, the server startup
simply halts.

Am I being unreasonable in trying to call these functions at this point
of the server startup, or is this just some stupid bug in my code?

I wish to call ShmemAlloc in order to simply create a shared reference
to the Veil shared memory segments that I will set up separately.

Thanks
__
Marc