signals returning results

[jcupitt gmail com]

Hi all,

I'd like to make a signal that can return a bool result. I've defined it with:

        progress_signals[SIG_UPDATE] = g_signal_new( "update",
                G_OBJECT_CLASS_TYPE( class ),
                G_SIGNAL_RUN_FIRST,
                G_STRUCT_OFFSET( ProgressClass, begin ),
                progress_update_accumulate, NULL,
                nip_BOOLEAN__INT_INT,
                G_TYPE_BOOLEAN, 2,
                G_TYPE_INT,
                G_TYPE_INT );

but then at runtime I get the message:

(nip2:73155): GLib-GObject-WARNING **: gsignal.c:1287: signal
"Progress::update" has return type `gboolean' and is only
G_SIGNAL_RUN_FIRST

Checking the source, the warning comes from:

  if (return_type != G_TYPE_NONE &&
      (signal_flags & (G_SIGNAL_RUN_FIRST | G_SIGNAL_RUN_LAST |
G_SIGNAL_RUN_CLEANUP)) == G_SIGNAL_RUN_FIRST)
    {
      g_warning (G_STRLOC ": signal \"%s::%s\" has return type `%s'
and is only G_SIGNAL_RUN_FIRST",

Why can't I make a RUN_FIRST signal that returns a boolean? I can't
see anything in the docs about this.

John