Re: Callback function gives crazy "size_t nmemb" value for simple http get operation (C++)
Date: Tue, 7 Apr 2009 21:37:48 +0200
On Sun, Apr 05, 2009 at 10:12:40AM -0400, A. Craig West wrote:
> 2009/4/5 Phil Blundell <pb_at_reciva.com>:
> > You need to provide a wrapper function to interface between the C and
> > C++ worlds, or make Book::write_html be a static member function rather
> > than an object method.
> The easiest thing to do in C++ is to pass a pointer to a static
> method. It needs to have the correct prototype,
While this works just fine and I've been doing it myself for years, I have
always had a bad feeling about it. In fact, I've switched over to 'extern
"C"' wrapper functions which then call the appropriate non-static method.
The thing is that AFAIK if you call a function with C++ linkage (including
static method) from C code and that C code thinks it's calling another C
function, strictly speaking the result is undefined.
'extern "C"' wrappers are a bit awkward because you have to declare them
all as friends of your classes, but IMHO they are a cleaner solution.
-- __ _ |_) /| Richard Atterer | GnuPG key: 888354F7 | \/¯| http://atterer.net | 08A9 7B7D 3D13 3EF2 3D25 D157 79E6 F6DC 8883 54F7 ¯ '` ¯Received on 2009-04-07