[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH 1/3] mini-os: add BUILD_BUG_ON()
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
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