Re: [Libguestfs] [libnbd PATCH 1/3] generator: Introduce REnum/RFlags return types
On 9/7/20 9:52 AM, Richard W.M. Jones wrote:
>> You used unsigned for RFlags, but shouldn't it be this
instead?
>>
>> + | RFlags (_) -> "uint32_t"
>
> Hmm. For Flags as input, we take uint32_t, but for
> get_handshake_flags which used to return RUint, we returned
> unsigned; as written, my patch preserved generated code in its
> entirety. Changing it to return uint32_t makes sense, but is a
> minor API change.
Oh I see, good point.
I think although technically it might not be an ABI change,
best to leave it as you wrote it.
Not only is it not an ABI change, but we got lucky: no one has ever
compiled libnbd on a platform where it would be an API change. Note
that pre-patch, our generated lib/unlocked.h had 'unsigned
nbd_get_handshake_flags' but our hand-written lib/handle.c had 'uint32_t
nbd_get_handshake_flags'. On every platform where libnbd compiles, the
two types are synonymous, so the API change factor is a non-issue
(platforms where it might not be the same could be a 32-bit platform
where 'uint32_t' is 'long', but no one has reported trying to build
libnbd on such a system). So I'll go ahead and make the change, with
the commit message giving this additional justification.
--
Eric Blake, Principal Software Engineer
Red Hat, Inc. +1-919-301-3226
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