How to fix: error: invalid conversion from 'const MyClass*' to 'MyClass*'

问题

I am getting this compile error:

error: invalid conversion from 'const MyClass*' to 'MyClass*'

Here is the code:

std::tr1::shared_ptr<MyClass> myClassA;
const MyClass* myClassB;
myClassA = std::tr1::shared_ptr<MyClass>(myClassB); // error here

I think I understand the error, just don't know how to fix. I need myClassB to be a const so how to convert/copy classB to a shared_ptr?

回答1:

You'll need a shared pointer to a const object:

std::tr1::shared_ptr<const MyClass> myClassA;
                     ^^^^^

回答2:

You can't go from a const MyClass to MyClass.

myClassA = std::tr1::shared_ptr< **const** MyClass>(myClassB);

来源：https://stackoverflow.com/questions/11484737/how-to-fix-error-invalid-conversion-from-const-myclass-to-myclass