16-byte memory align requirement
lazarus / 8-Other

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scribly · 2009-02-12 21:02

I need to call a routine that is really picky about the pointer being
16-byte aligned
Is there a way in the ide settings or compile setting parameters to
force 16-bit alignment (or better, just specify that particular
structure to be on an address that is 16-byte aligned)

I guess I could allocate +12 bytes and then shift the pointer address
so it is aligned and make sure to free the right pointer base when
done...
Or use windows' Virtualalloc which always returns a whole page
But it'd be nice if that wasn't necesary

Function in question is windows 64's: GetThreadContext and
SetThreadContext

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Phil · 2009-02-12 21:12

I assume you're referring to a CONTEXT record?

See the FPC prog.pdf and search for "align" and "packed".

Thanks.

-Phil

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scribly · 2009-02-12 22:55

Thanks, I tried {$PACKRECORDS 16} but it still allocated the context
structure on a 8 byte boundary, including the elements in it. (bug?)

anyhow, i'll just go with the offset shift and just deal with it
specifically in the constructor and destructor of the class that uses
it

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felipemdc · 2009-02-16 12:20

You should post this question in the Free Pascal mailling list. You
will get better answers there.