C/C++ inline, __forceinline, __attribute__
強制的にinlineしたい場合
__forceinline function_declarator; // Microsoft Specific
__attribute__((always_inline)) function_declarator; // gcc
http://msdn.microsoft.com/ja-jp/library/z8y1yy88.aspx
http://stackoverflow.com/questions/8381293/how-do-i-force-gcc-to-inline-a-function