Re: [Xen-devel] [PATCH 1/3] mini-os: add BUILD_BUG_ON()

[Tim Deegan <tim@xxxxxxx>]

At 15:25 +0100 on 02 Jul (1404311125), Jan Beulich wrote:
> Just copy over what the hypervisor currently uses.

Careful of licenses here, please.  While there might be an argument
that BUILD_BUG_ON is simple enough to be uncopyrightable (and indeed
it looks like you wrote the current Xen implementation anyway), I
don't think you can just lift the whole thing, comments and all, into
a BSD-licensed file.

Cheers,

Tim.

> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
> 
> --- a/extras/mini-os/include/lib.h
> +++ b/extras/mini-os/include/lib.h
> @@ -54,6 +54,20 @@
>  #include <xen/event_channel.h>
>  #include "gntmap.h"
>  
> +#if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 6)
> +/* Force a compilation error if condition is true */
> +#define BUILD_BUG_ON(cond) ({ _Static_assert(!(cond), "!(" #cond ")"); })
> +/* Force a compilation error if condition is true, but also produce a
> +   result (of value 0 and type size_t), so the expression can be used
> +   e.g. in a structure initializer (or where-ever else comma expressions
> +   aren't permitted). */
> +#define BUILD_BUG_ON_ZERO(cond) \
> +    sizeof(struct { _Static_assert(!(cond), "!(" #cond ")"); })
> +#else
> +#define BUILD_BUG_ON_ZERO(cond) sizeof(struct { int:-!!(cond); })
> +#define BUILD_BUG_ON(cond) ((void)BUILD_BUG_ON_ZERO(cond))
> +#endif
> +
>  #ifdef HAVE_LIBC
>  #include <sys/queue.h>
>  #include <stdio.h>
> 
> 
> 

> mini-os: add BUILD_BUG_ON()
> 
> Just copy over what the hypervisor currently uses.
> 
> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
> 
> --- a/extras/mini-os/include/lib.h
> +++ b/extras/mini-os/include/lib.h
> @@ -54,6 +54,20 @@
>  #include <xen/event_channel.h>
>  #include "gntmap.h"
>  
> +#if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 6)
> +/* Force a compilation error if condition is true */
> +#define BUILD_BUG_ON(cond) ({ _Static_assert(!(cond), "!(" #cond ")"); })
> +/* Force a compilation error if condition is true, but also produce a
> +   result (of value 0 and type size_t), so the expression can be used
> +   e.g. in a structure initializer (or where-ever else comma expressions
> +   aren't permitted). */
> +#define BUILD_BUG_ON_ZERO(cond) \
> +    sizeof(struct { _Static_assert(!(cond), "!(" #cond ")"); })
> +#else
> +#define BUILD_BUG_ON_ZERO(cond) sizeof(struct { int:-!!(cond); })
> +#define BUILD_BUG_ON(cond) ((void)BUILD_BUG_ON_ZERO(cond))
> +#endif
> +
>  #ifdef HAVE_LIBC
>  #include <sys/queue.h>
>  #include <stdio.h>

> _______________________________________________
> Xen-devel mailing list
> Xen-devel@xxxxxxxxxxxxx
> http://lists.xen.org/xen-devel


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel