If dest is null, free src; otherwise, moves src into *dest.
The error variable dest points to must be null.
src must be non-null.
Note that src is no longer valid after this call. If you want
to keep using the same GError*, you need to set it to null
after calling this function on it.
If
destisnull, freesrc; otherwise, movessrcinto*dest. The error variabledestpoints to must benull.srcmust be non-null.Note that
srcis no longer valid after this call. If you want to keep using the same GError*, you need to set it tonullafter calling this function on it.