Dealing with FFI and return values is very tricky; this API allows
sharing the bits to do it between gobject-introspection and gjs (and
potentially other FFI binding consumers).
**NOTE** I swapped the order of the arguments, under the premise that
out arguments should generally be last.
https://bugzilla.gnome.org/show_bug.cgi?id=668902
Adapted from the fixes for (see bug 665152). It makes sure values are
properly converted between glib and FFI, which is critical for big
endian architectures.
Patch adjusted to use GIArgument instead of custom union types
by Colin Walters <walters@verbum.org>
https://bugzilla.gnome.org/show_bug.cgi?id=668902
Any annotation where the key has a dot in the name will go into the
attribute list. For example
* @arg: (foo.bar baz): some arg
the parameter @arg will get the attribute with key foo.bar and value
baz. This also works for.
* Returns: (foo.bar2 baz2): the return value
Also add tests for this new feature.
See https://bugzilla.gnome.org/show_bug.cgi?id=571548
Signed-off-by: David Zeuthen <davidz@redhat.com>