On 2/26/2010 5:44 AM, Ed Smith-Rowland wrote:
Huh. I would have *sworn* that sizeof(long double) was 10 not 16 even
though we know it was 80 bits.
As you indicated before, sizeof gives the amount of memory displaced by
the object, including padding. In my experience with gcc, sizeof(long
double) is likely to be 12 on 32-bit platforms, and 16 on 64-bit
platforms. These choices are made to preserve alignment for 32-bit and
128-bit objects respectively, and to improve performance in the 64-bit
case, for hardware which doesn't like to straddle cache lines.
It seems the topic would have been more appropriate for gcc-help, if
related to gcc, or maybe comp.lang.c, if a question about implementation
in accordance with standard C.
--
Tim Prince
