On Wed, 05 Sep 2018 16:55:03 +0100, David Howells wrote: > >The bkey struct defined by bcache is embedded in the jset struct. However, >this is illegal in C++ as there's a "flexible array" at the end of the struct. >Change this to be a 0-length struct instead. > >- __u64 ptr[]; >+ __u64 ptr[0]; As per the C++ standard, it is _also_ illegal to declare an array of size zero. """it [the array size expression] shall be a converted constant expression of type std::size_t and its value shall be greater than zero.""" —http://eel.is/c++draft/dcl.array That makes both "__u64 ptr[]" and "__u64 ptr[0]" *implementation-specific extensions*. 3rd party tooling (concerns both C and C++): Coverity Scan (IIRC) treats "__u64 ptr[0]" as an array of "definitely-zero" size. Writing to any element will outright flag an out-of-bounds violation. That is sensible, since only "ptr[]" was standardized. Conclusion: So please, do never use __u64 ptr[0].
