15 Jul
2007
15 Jul
'07
4:53 p.m.
Hi!
Sorry to bother again. But I have the following problem I can't solve.
I need to wrap some readline-code in my c++-class. Readline has some
function-pointers you can set to a function you wrote yourself. So I did. The
sinature of my function ALMOST matches that expected by readline, but it
complains about the class part of my signature:
my function:
char** (Midish_rl::*)(const char*, int, int);
Readline expects:
char8* (*)(const char*, int, int);
I tired writing a wrapper function, but for that I need some object, I just
tried:
char** wrapper(const char *text, int start, int end)
{
return my_ui.real_function(text,start,end);
}
The code is divided between a few files, so I couldn't just a a global
object 'my_ui', which was known at all times.
Does anyone have an idea how to solve it?
Note: I don't want to use any external class-libraries, which might perform
the task, because of dependencies. Anyway, there are no standard lib, that do
that, not that I'm aware of at least.
Kindest regards
Julien
--------
Music was my first love and it will be my last (John Miles)
======== FIND MY WEB-PROJECT AT: ========
http://ltsb.sourceforge.net
the Linux TextBased Studio guide
======= AND MY PERSONAL PAGES AT: =======
http://www.juliencoder.de
15 Jul
15 Jul
5:05 p.m.
On Sun, 2007-07-15 at 20:52 +0200, Julien Claassen wrote:
If the Readline callback format does not have a parameter to pass user
data (which is a rather crappy design if that's the case) you have to
use a global variable of some sort. You can declare it 'extern' in a
header that you include in all files that need it, or make it a
singleton class with a static get_instance() member, or some similar
technique.
--ll
16 Jul
16 Jul
2:49 p.m.
On 7/15/07, Julien Claassen <julien(a)c-lab.de> wrote:
You need something like std::mem_fun. Have you looked at Boost
(http://www.boost.org)? I think boost::mem_fn will do what you want.
You could also cobble something together on your own. If your
Midish_rl class is a singleton (i.e. you only allocate one object of
that type in you program), you could add some static wrapper methods.
Otherwise, write your own member function adapters classes specific to
your situation.
4:57 p.m.
You need something like std::mem_fun. Have you looked
at Boost
(http://www.boost.org)? I think boost::mem_fn will do what you want.
Unfortunately that won't work. std::mem_fun and boost::mem_fn create
functors which can be used with STL algorithms and the like, but are
completely different from C functions (or function pointers). The way
they are used looks similar, but it's not the same thing.
There simply is no pretty solution to this problem, you'll have to use
a global (or static member) function in some way...
8:30 p.m.
Hi!
Thanks both of you! I used a singleton, but now ran into some internal
problems. Readline has some internal variables and I don't know where theyget
free'd or something. I try to work out the problem with my gdb, but so far no
luck. To be frank: it's a bitch, this one... :-(
Anyone willing to have a look at my code (about 700 lines... not all
important to the problem...?
Kindes tegards
Julien
--------
Music was my first love and it will be my last (John Miles)
======== FIND MY WEB-PROJECT AT: ========
http://ltsb.sourceforge.net
the Linux TextBased Studio guide
======= AND MY PERSONAL PAGES AT: =======
http://www.juliencoder.de
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4 comments
4 participants
participants (4)
-
Dominic Sacré -
Julien Claassen -
Lars Luthman -
Paul Coccoli