FFI kick start

[john]

Hi guilers...

I am trying to get to grips with manually wrapping C functions but
need some pointers. I have a C function:

packedEncode *initializeEncode(char *pdu, int size)

with:

typedef struct {
  char *pdu;
  ...

} packedEncode;

It takes a pointer to some storage (char *pdu) which will be mutated
by other wrapped C functions and finally retrieved. I am running into
segfault problems when it comes to mutating the data from C and then
trying to access it. I would really appreciate some pointers or some
boiler plate code for handling this type of function to get me
rolling.

TIA,

John.