On 04/06/2017 04:43 PM, Jonathan Wakely wrote:
On 06/04/17 16:23 +0200, Richard Biener wrote:
On Thu, 6 Apr 2017, Florian Weimer wrote:
On 04/06/2017 04:11 PM, Bernd Edlinger wrote:
> I think it is not too complicated to done in the C++ FE.
> The FE looks for array of std::byte and unsigned char,
> and sets the attribute when the final type is constructed.
>
> What I am trying to do is just extend the semantic of may_alias
> a bit, and then have the C++ FE use it in the way it has to.
We also need this for some POSIX and Linux kernel interfaces. A
C++-only
solution would not help with that.
Example(s)?
sockaddr_storage comes to mind.
Right. The kernel also has many APIs which return multiple
variable-length data blocks, such as getdents64, and many more
interfaces in combination with read/recv system calls. Variable length
means that you cannot declare the appropriate type after the first data
item, so you technically have to use malloc.
POSIX interfaces which exhibit a similar pattern are getpwnam_r and
friends, but for them, you can probably use malloc without ill effect
(although there are still performance concerns).
Thanks,
Florian
