Re: [Qemu-trivial] [Qemu-devel] [PATCH RESEND 1/3] usb-ccid: make ccid_write_data_block() cope with null buffers

[Markus Armbruster]

Gerd Hoffmann <address@hidden> writes:

> On Do, 2017-03-23 at 13:41 +0100, Markus Armbruster wrote:
>> Gerd Hoffmann <address@hidden> writes:
>> 
>> >   Hi,
>> >
>> >>  oops, there are hard-coded calls with NULL/0. I suppose to fix clang
>> >> warning, it would need to check if data != null for memcpy.
>> >
>> > I'd check for len > 0, and in that if branch we can also assert on data
>> > == NULL and thereby check that len and data are consistent.
>> 
>> If len is non-zero but data is null, memcpy() will crash just fine by
>> itself, so why bother asserting.
>
> To make clang happy?  But maybe clang is clever enough to figure data
> can't be null at that point in case we call memcpy with len != 0
> only ...

If Clang needs another hint to become happy, then an assertion is a fine
way to provide it.