[PATCH] Define libc_max_align_t

[Rich Felker]

On Thu, Apr 02, 2015 at 12:01:34AM +0200, Andreas Schwab wrote:
> Florian Weimer <fweimer@redhat.com> writes:
> 
> > +/* This mirrors the C11 max_align_t type provided by GCC, but it is
> > +   also available in C99 mode.  */
> > +typedef struct {
> > +  long long ll __attribute__ ((__aligned__ (__alignof__ (long long))));
> > +  long double ld __attribute__ ((__aligned__ (__alignof__ (long double))));
> > +} libc_max_align_t;
> 
> Why aren't the attributes no-ops?

Because gcc is insane.

On gcc, __alignof__ returns the "preferred alignment for optimization"
that gcc would use allocating such objects individually, not the "ABI
alignment" that would be used in structs, etc.

Rich