Re: glib2 deprecated declarations failing on clang16

On 4 Jul 2023, at 14:37, Nuno Teixeira <eduardo@freebsd.org> wrote:
> 
> I'm getting build errors from current with www/bluefish about deprecated glib2 declarations and causing build to fail with clang16:
> ---
> /usr/local/include/glib-2.0/glib/gmacros.h:1262:37: note: expanded from macro 'G_DEPRECATED'
> #define G_DEPRECATED __attribute__((__deprecated__))
>                                     ^
> mv -f .deps/bluefish.Tpo .deps/bluefish.Po
> bftextview2_langmgr.c:2665:2: warning: 'g_thread_create_full' is deprecated: Use 'g_thread_new' instead [-Wdeprecated-declarations]
>         g_thread_create_full(build_bflang2scan_thread, NULL, 0, FALSE, FALSE, G_THREAD_PRIORITY_LOW, &gerror);
> ---
> 
> Any help is welcome on finding out its cause.
> 
> a related issue: https://github.com/PCSX2/pcsx2/issues/3315
> 
> Build log: https://pkg-status.freebsd.org/beefy17/data/main-i386-default/pf46bd2c58425_s0631830a7a/logs/bluefish-2.2.14.log

The actual error is an incompatible callback function signature:

bftextview2_autocomp.c:432:2: error: incompatible function pointer types passing 'gboolean (GtkLabel *, gchar *, gpointer)' (aka 'int (struct _GtkLabel *, char *, void *)') to parameter of type 'GCallback' (aka 'void (*)(void)') [-Wincompatible-function-pointer-types]
g_signal_connect(acw->reflabel, "activate-link", acw_label_active_link_lcb, acw);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/local/include/glib-2.0/gobject/gsignal.h:515:59: note: expanded from macro 'g_signal_connect'
g_signal_connect_data ((instance), (detailed_signal), (c_handler), (data), NULL, (GConnectFlags) 0)
^~~~~~~~~~~
/usr/local/include/glib-2.0/gobject/gsignal.h:411:25: note: passing argument to parameter 'c_handler' here
GCallback c_handler,
^

I have seen these more often with glib-based applications. In some cases
it is feasible to fix the callback function to have the correct
signature, in other cases you can slap a cast in place. Or, if the
affected code is vala-generated (also happens), the big hammer is to
suppress the warning(s).

-Dimitry