调查我是否需要使用auto_ptr [英] Investigating whether I need to use a auto_ptr
问题描述
我在这样的课程中有一个方法
class myClass
{
... ctros，dtor，等...
string myClassMethod（）
{
string myString ="" ;;
...更多代码.....
myString ="新值" ;;
返回（ myString）;
}
};
所以我的问题是，这是安全还是退货字符串丢失
当执行超出范围时，在这种情况下我会更好地以/ b
以auto_ptr的形式传回一个字符串指针？
TIA，
Pep。
I have a method in a class like this
class myClass
{
... ctros, dtor, etc ...
string myClassMethod()
{
string myString = "";
... more code ....
myString = "new value";
return(myString);
}
};
So my question is, is this safe or will the returned string go missing
when execution goes out of scope, in which case I would be better of
passing back a string pointer in the form of a auto_ptr?
TIA,
Pep.
推荐答案
Pep写道：
....
Pep wrote:
....
string myClassMethod（）
{
string myClassMethod()
{
....
....
>
所以我的问题是，这是安全还是返回的字符串去当执行超出范围时，缺少
，在这种情况下，我会更好地回复一个以auto_ptr形式返回字符串指针的
？
>
So my question is, is this safe or will the returned string go missing
when execution goes out of scope, in which case I would be better of
passing back a string pointer in the form of a auto_ptr?
std :: string类是一个可以复制的容器。你在这里做什么是
返回myString的副本，所以没有必要管理字符串生命周期的
。
另一方面，如果你写了：
std :: string& myClassMethod（）
....这可能是未定义的。
the std::string class is a container that can be copied. What you''re
doing here is returning a copy of myString so there is no need to manage
the lifetime of the string.
On the other hand if you had written:
std::string & myClassMethod()
.... this would have been undefined.
Gianni Mariani写道：
Gianni Mariani wrote:
Pep写道：
...
Pep wrote:
...
string myClassMethod （）
{
string myClassMethod()
{
...
...
所以我的问题是，这是安全还是返回的字符串会丢失
当执行超出范围时，在这种情况下我会更好
传回一个字符串指针以auto_ptr的形式？
So my question is, is this safe or will the returned string go missing
when execution goes out of scope, in which case I would be better of
passing back a string pointer in the form of a auto_ptr?
std :: string类是一个可以复制的容器。你在这里做什么是
返回myString的副本，所以没有必要管理字符串生命周期的
。
另一方面，如果你写了：
std :: string& myClassMethod（）
......这可能是未定义的。
the std::string class is a container that can be copied. What you''re
doing here is returning a copy of myString so there is no need to manage
the lifetime of the string.
On the other hand if you had written:
std::string & myClassMethod()
... this would have been undefined.
因此，在检查最终生产版本时我需要应用的规则
我的类库将确保其中的所有对象
图书馆有副本ctor？
另外，不要返回我不会尝试的参考文件吗？
干杯，
Pep。
So the rule I need to apply when checking the final production version
of my class library would be to ensure that all objects within the
library have a copy ctor?
Also, do not return references which I don''t attempt as a rule?
Cheers,
Pep.
Pep skrev：
Pep skrev:
Gianni Mariani写道：
Gianni Mariani wrote:
[snip]
[snip]
>
因此，在检查最终生产版本时我需要应用的规则
我的类库将确保
内的所有对象
图书馆有副本ctor？
>
So the rule I need to apply when checking the final production version
of my class library would be to ensure that all objects within the
library have a copy ctor?
第一条规则是：资源管理（无论是内存，句柄还是
其他任何东西）应该是自动的。特别是，释放资源
应该在析构函数中而不是其他地方。
The first rule is: resource management (be it memory, handles or
anything else) should be automatic. In particular, releasing a resource
should happen in a destructor and nowhere else.
>
另外，不要返回我不作为规则尝试的参考文献？
>
Also, do not return references which I don''t attempt as a rule?
永远不要返回本地数据的引用（包括指针）。 （
是规则＃2），
/ Peter
Never return references (this includes pointers) to local data. (that
was rule #2),
/Peter
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