Dear Maintainer,

When compiling software that includes a gtkmm header file, using g++, the
software fails to compile due to this error:

/usr/include/gtkmm-4.0/gdkmm/cursor.h:30:7: error: conflicting declaration
‘using GdkCursorClass = struct _GdkCursorClass’

In file included from /usr/include/glib-2.0/gobject/gobject.h:26,
                 from /usr/include/glib-2.0/gobject/gbinding.h:31,
                 from /usr/include/glib-2.0/glib-object.h:24,
                 from /usr/include/glibmm-2.68/glibmm/class.h:21,
                 from /usr/include/glibmm-2.68/glibmm/objectbase.h:21,
                 from /usr/include/glibmm-2.68/glibmm/object.h:29,
                 from /usr/include/gtkmm-4.0/gdkmm/clipboard.h:25,
                 from /usr/include/gtkmm-4.0/gtkmm/widget.h:32:
/usr/include/gtk-4.0/gdk/gdkcursor.h:38:1: note: previous declaration as
‘typedef struct GdkCursorClass GdkCursorClass’

This seems to hold for including most of the header files, in this case e.g.
the widget.h file:

[..]
In file included from /usr/include/gtkmm-4.0/gtkmm/widget.h:33,
                 from /usr/include/gtkmm-4.0/gtkmm/box.h:26,
[..]

This affects e.g. the build of the aoflagger package (and probably many
others), which no longer builds against the current version of
libgtkmm-4.0-dev.

Regards,
André

Version: 4.24.0-1

I believe this issue is fixed in gtkmm4.0 4.24.0-2 which is in
Unstable and should migrate to Testing in the next day or so. Sorry
for the inconvenience.

Thank you,
Jeremy Bícha

...

This looks like an incompatibility between older gtkmm4.0 and newer
GTK4. Please try upgrading libgtkmm-4.0-dev to the version from
unstable.

     smcv