[PyKDE] More sip on C fun!

[Jonathan Gardner]

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I have three questions about using sip to wrap C->C++. I have done all the 
"easy" stuff. If anyone would like to see my code, I'll post it.

1) I am running into a bit of a problem translating a struct to sip.

The struct in question has an attribute 'char **fieldNames' -- which is 
meant to be a null-terminated list of null-terminated strings. Of course, 
sip doesn't know what to do with this.

Is there something akin to '%MemberCode' that I can put after the attribute 
that allows me to specify how to set and get the value 'fieldNames'? Or, do 
I need to wrap it with a C++ class that doesn't provide a direct interface 
to fieldNames?

2) One function requires a struct as an argument. This struct is so deep 
into C it doesn't make any sense to translate it to Python at all (it has a 
union with a void pointer and an integer for one of the attributes, and 
half the other attributes describe the length and types of the other 
attributes). Can I just invent a function that takes a dict or a list as an 
argument in place of the struct? How would I specify this?

Here is the prototype for reference (wrapped as far as I dare go in C++)
:
class Conn {
	...
	public:
	result *fn(int fnid, int *result_buf, int *result_len, int result_is_int,
		const PQArgBlock *args, int nargs);
	...
};

3) There is a callback function that I would like to use. How would I go 
about doing this in sip? What kind of function should I put as the 
callback? What kind of arguments should I expect from sip?

Let's just keep it simple:

The callback prototype: typedef void (*callback_func)(int);

The "set callback" prototype: int set_callback(callback_func *);
(And there is a corresponding release_callback() function as well, of 
course).

What I would like to see in python:

def callback(x):	print x
set_callback(callback)

how do I get from C to Python via sip?

- -- 
Jonathan Gardner
jgardner at jonathangardner.net
(was jgardn at alumni.washington.edu)
Live Free, Use Linux!
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