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By default, class objects can be copied. In particular, a class object can be initialized with a copy of another object of the same class. This can be done even where constructors have been declared.
By default, the copy of a class object is a copy of each member. If that default is not the behavior wanted for a class X, a more appropriate behavior can be provided by defining a copy constructor, X::X(const X&).
By Bjarne Stroustrup
If the class definition does not explicitly declare a copy constructor and there is no user-declared move
constructor, a copy constructor is implicitly declared as defaulted (8.4). Thus, for the class definition
struct X { X(const X&, int);
};
a copy constructor is implicitly-declared. If the user-declared constructor is later defined as
X::X(const X& x, int i =0) { /∗ ... ∗/ }
then any use of X’s copy constructor is ill-formed because of the ambiguity; no diagnostic is required.
12.8 Copying and moving class objects, Programming Languages — C++, ISO/IEC JTC1 SC22 WG21 N 3092 |
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楼主: wzlxx_
发表于 2010-06-07 21:18
发表于 2010-06-07 21:57
我就是忘记了这一点才弄看了半天代码没有发现呢，G++编译过的可执行文件似乎没有多次free，程序运行的很正常，不过潜在的问题我不知道。不过同样的代码在VC6.0根本无法执行
发表于 2010-06-08 11:32
