[haiku-gsoc] Re: Licensing questions
- From: Hamish Morrison <hamishm53@xxxxxxxxx>
- To: haiku-gsoc@xxxxxxxxxxxxx
- Date: Sat, 10 Jun 2017 22:04:52 +0100
On 09/06/2017 18:03, Vivek Roy wrote:
Yet again, in types.h there is strictly rcu_head where they have used
__aligned(size of(void *))
I can see that __aligned is defined in posix/arch and compat/freebsd_network
I haven't included any of those and am getting an error "expected
declaration specifiers or '...' before 'sizeof' "
A Google search gave me possible reasons being, syntax errors and
circular dependencies. I checked for both, found none.
Help?
__aligned is just a macro that tells the compiler that the type in
question aught to be aligned on the boundary given (in this case given
the same alignment as a pointer). Typically fundamental types will be
aligned on their size (an int on a 4 byte boundary, longs on 8 byte
boundaries, etc). But using a directive like this you can force
alignment to a larger boundary.
It will expand to some compiler-dependent directive for configuring
alignment e.g. for gcc it would be something like:
__attribute__((aligned(sizeof(void*))))
Since we only build with gcc you could just replace this with the above
(I believe clang also supports this syntax).
Or you could define a macro somewhere e.g.
#define __aligned(x) __attribute__((aligned(x)))
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