64비트 리눅스 플랫폼에서

printf("%ld\n", sizeof(long double));

하면 16 나오는데

 10 typedef struct __num_element
 11 {
 12         struct __num_element*   mpPrev;
 13         struct __num_element*   mpNext;
 14         char*                   mpValue;

 15         long double             mNumerKey;
 16 } NumberElement;

이건 왜

printf("%ld\n", sizeof(NumberElement));

하면 48 나옴 -_-???