g_return_if_fail (and friends) documentation does not show on docs.gtk.org
This macro is fully documented in the source, but the online docs just say "No description available." (same for other related macros such as g_return_val_if_fail
etc.)
I think this is especially a problem since the behaviour of these macros is rather counter-intuitive (i.e. that they may actually not return, depending on the build configuration).