is used to hold a pointer to <structname>FuncCallContext</>

across calls.

<programlisting>

typedef struct

typedef struct FuncCallContext

{

/*

* Number of times we've been called before

*

* call_cntr is initialized to 0 for you by SRF_FIRSTCALL_INIT(), and

* incremented for you every time SRF_RETURN_NEXT() is called.

*/

uint32 call_cntr;

uint64 call_cntr;

/*

* OPTIONAL maximum number of calls

* If not set, you must provide alternative means to know when the

* function is done.

*/

uint32 max_calls;

uint64 max_calls;

/*

* OPTIONAL pointer to result slot