Linux判断大小尾数(big-endian,little-endian)的方法
    static union
{
  char c[4];
  unsigned char l;
} endian_test={ {'l','?','?','b'} }
#define ENDIANNESS ( (char)endian_test.l )
if (ENDIANNESS == 'l')
//little endian 
else 
//big endian 
http://www.cnblogs.com/leezhm/archive/2011/07/19/2110864.html