dbus-internals: add _DBUS_ALIGNOF

This is useful when making static assertions about our types'
properties.

Signed-off-by: Simon McVittie <simon.mcvittie@collabora.co.uk>
Reviewed-by: Thiago Macieira <thiago@kde.org>
Bug: https://bugs.freedesktop.org/show_bug.cgi?id=94136

diff --git a/dbus/dbus-internals.h b/dbus/dbus-internals.h
index 3eb8749f3ed5008ef7fff4479e8f918d2e85c5e2..df8e9643dd9673ac2eff7b17a2c658eb838bb06e 100644 (file)
--- a/dbus/dbus-internals.h
+++ b/dbus/dbus-internals.h
@@ -195,6 +195,9 @@ extern const char *_dbus_return_if_fail_warning_format;
 #define _DBUS_STRUCT_OFFSET(struct_type, member)       \
     ((intptr_t) ((unsigned char*) &((struct_type*) 0)->member))
 
+#define _DBUS_ALIGNOF(type) \
+    (_DBUS_STRUCT_OFFSET (struct { char _1; type _2; }, _2))
+
 #ifdef DBUS_DISABLE_CHECKS
 /* this is an assert and not an error, but in the typical --disable-checks case (you're trying
  * to really minimize code size), disabling these assertions makes sense.