从Empty class 看 is_Empty
2009-07-25 16:51
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在 type_traits中有个is_Empty函数，用来判断一个class是否是空类
如: struct A {}; sizeof(A) = 1;
struct B : public A {int i}; sizeof(B) = 4
struct C {int i} sizeof(C) = 4
则if sizeof(C) == sizeof (B)则A为空
如: struct A {}; sizeof(A) = 1;
struct B : public A {int i}; sizeof(B) = 4
struct C {int i} sizeof(C) = 4
则if sizeof(C) == sizeof (B)则A为空
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