Re: posting message to text view from C-function
Re: posting message to text view from C-function
- Subject: Re: posting message to text view from C-function
- From: j o a r <email@hidden>
- Date: Fri, 6 May 2005 11:13:06 +0200
On 6 maj 2005, at 10.53, Roland Silver wrote:
The question becomes, where does the CALLER get a reference to the
text view, so as to provide it as a parameter?
In other words, the caller, itself a C-function (call it
cFunction2), will have to invoke plainCFunction this way:
... plainCFunction(textView); ...
so if it can't conjure up the reference to the text view, how does
IT get it??
The simplified answer is that if it doesn't get it via a parameter,
it must have created it.
This is not a problem that is specific to C-functions. It works in
exactly the same way for Objective-C methods.
The only thing that differs is that an ObjC method is passed a
"secret" parameter - the reference to "self". Via this parameter you
get access to the instance variables of the object in question.
I think that your problem is that you have an existing ObjC object
graph, in a Cocoa application, and you have some C-functions that you
want to use in that context. Right so far? You need to think about
what event that triggers the C-functions to be called in the first
place. When the first C-function is called, it needs to have
knowledge about some part of the ObjC object graph, to be able to
access the data in that graph. If your C-function is called from an
ObjC method, just pass along the required parameters as have been
discussed previously in this thread. If the C-function is called from
some sort of callback, there is often (always?) some sort of context
(void *) pointer that can be used for that same purpose.
If you want more help, I think you need to give a concrete example of
what you're trying to do.
j o a r
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