a

a.c

PG_FUNCTION_INFO_V1(addTen);
Datum addTen(PG_FUNCTION_ARGS) {
    int32            i;
    FuncCallContext *funcctx;
    int              call_cntr;
    int              max_calls;

    // Code executed only on first call of the function
    if (SRF_IS_FIRSTCALL()) {
        MemoryContext oldcontext;
        // Initializing the function context for cross call persistence
        funcctx = SRF_FIRSTCALL_INIT();
        // Context memory for multi calls
        oldcontext = MemoryContextSwitchTo(funcctx -> multi_call_memory_ctx);
        // Getting argument (original integer)
        if (PG_ARGISNULL(0))
                    ereport(ERROR,
                            (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
                             errmsg("Table cannot be NULL")));
                             funcctx->user_fctx = (void*)palloc(sizeof(int32));
           *((int32*)funcctx->user_fctx) = PG_GETARG_INT32(0);

        // Alloacting space to save the integer and make it persistent between calls
      //  funcctx->user_fctx = &i;
        // Maximum number of calls
        funcctx -> max_calls = 10;

        MemoryContextSwitchTo(oldcontext);
    }

    // Code executed on each call (first one included)
    // Retrieving values from function context
    funcctx = SRF_PERCALL_SETUP();
    call_cntr = funcctx->call_cntr;
    max_calls = funcctx -> max_calls;

    if (call_cntr < max_calls) {
        int32* temp = funcctx->user_fctx;
        i = *temp;
        SRF_RETURN_NEXT(funcctx, i + call_cntr);
    } else {    // Done
        SRF_RETURN_DONE(funcctx);
    }
}