[xcb] Memory management in XCB (was: XCB polling and

[Carl Worth]

On Jul 8, Jamey Sharp wrote:
 > As far as I'm concerned, XCB doesn't have this ambiguity. If it returns
 > a pointer, it's the caller's responsibility to free it.

That's also a valid approach to providing a consistent API.

 > There is one other exception: XCBQueryExtensionCached. This function
 > returns the requested item directly out of the cache. Following a style
 > tip I read somewhere, I tagged the return value "const" to indicate that
 > it should not be freed. (I also commented this aspect of the function's
 > contract.)

Right, when I scanned looking for functions returning pointers, I had
noticed this one, (along with the comment warning against
freeing). That's what got me started thinking about this. I hadn't
noticed the "const".

 > However, the application in general has no way of knowing how much
 > memory to allocate for replies. For this reason, I think the memory for
 > replies must be allocated inside XCB, and a pointer to it returned.

Right. And I wasn't actually proposing changing this. Mostly I was
just rambling. :-)

-Carl

-- 
Carl Worth                                        
USC Information Sciences Institute                 cworth@east.isi.edu
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