Re: [gtkmm] On Glib::IOChannel wrappers

[MHL Schulze t-online de (Martin Schulze)]

Am 12.09.2002 23:27 schrieb(en) Tassos Bassoukos:
> Hi all,
> lately i've felt the need to wrap libgnet, a socket library intended for
> use by Gtk+ programs. The major problem I've stumbled upon is that gnet
> is
> returning GIOChannel's (not int's), which are not wrapped in glibmm.
>
> I've now written some preliminary wrappers, but they need some polishing
> first; most importantly, I need enlightenment on some items so that they
> will fit well with the rest of Glib:
>
>  * IOChannels have the potential for lots of errors, as evidenced by the
> ever-present GError**. Should these be thrown as C++ exceptions by the
> wrappers, or should I use a trailing Glib::Error*& parameter?
>
>  * Glib::Source (as currently implemented) cannot wrap non-glibmm
> generated GSource's, ergo Glib::IOChannel cannot generte watches,

I agree with Murray: A patch adding Glib::Source::Source(GSource* source)
would be welcome (but probably non-trivial)! :-)

> removing
> one of IOCHannels more useful features. One could use
> SignalIO.connect(int
> fd,IOCondition cond), but that is non-portable as Win32 sockets are not
> represented as ints, and are not regular file descriptors. Also, it looks
> ugly :-)

1. Just to make clear: You are talking about sockets and not about pipes
or something similar that is represented by an int ("HANDLE") in Win32 ?!
I do hope that the latter is supported by Glib::IOSource. Since there was
no feedback so far regarding that matter and I'm not using Win32 I don't
really know, however! Does GIOChannel support Win32 sockets anyway and how?

2. What do you mean by "ugly"? Can you think of a more elegant API?

3. Talking about portability: In the very first lines of your patch I
notice a call to g_io_channel_unix_new(). Are you sure this is a
portable function? I remember that I avoided it in the implementation
of Glib::IOSource. Also are you sure that g_io_channel_new_file() is
portable?

4. I don't want to be ignorant, but why do you need GIOChannel at all?
What functionality does it provide that ANSI C++ streaming classes don't?
Support for Win32 sockets??

Regards,

  Martin