Hi Prawit,
>Does anybody has any explaination [why the compiler allocates more than specified]?
Alignment.
You didn't specify what platform, GCC version (3.3.4? 3.4.0?), and compile options you are using. If you are not generated optimized code, the code may not be optimized.
It is also possible that one of the GCC Gnurus made a boo-boo. Rare, but can happen. Especially between optimizations that are in contention, which may have unintended side-effects on different platforms. (I discovered 3 such issues, on GCC 2.95 on Solaris. They're all fixed now.)
HTH, --Eljay
