>> hi ,
> i want to know how "align" works in gcc .
> i use this in my program, run in a X86 box, RedHat 6.2 full installed:
>> int a __attribute__ ((aligned(8)));
>> printf("size of a : %d \n", sizeof(a));
>> i want it's size be 8 bytes, by i get 4.
> anyone can tell me how to use align in detail?
The size of an int will always be 4 bytes. However, if you were to
define a struct with one integer element, I believe that the size of the
struct would be 8. align affects the amount of padding space set aside
in memory after the end of that variable, so if a is at address 0x0, the
next variable will be stored (at earliest) in 0x8. But the int is still
of size 4. If you want ints that are 8 bytes long, you should probably
As an aside, is an int always the same size as a memory address (ie. 4
bytes on 32 bit machines, 8 bytes on 64 bit), or is it always 4 bytes?
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