Cause:
References should be instantiated to refer to a valid object or a function. When rvalues are used to initialize references, in certain cases compiler creates temporary objects and bind them to references . Temporaries are destroyed at the end of the full expression in which it was created. So it is dangerous to initialize references with temporary.
Example:
Cause:
Temporaries are destroyed as the last step in evaluating the full-expression that contains the point where they were created. In other words temporaries are destroyed when control reaches the terminating semicolon of the full-expression in which they were created.
If an object pointer is instantiated with a temporary, the pointer will become a dangling pointer as temporary gets destroyed immiediately after statement ends.
Example:
Following code shows an example where the problem can occur:
Cause:
Compiler generates default assignment operator and copy constructor for class that does not define one. It is memberwise copy of the data members of an object. As references cannot be modified once initialized, the assignment operator generated for a class having reference as member would be invalid. So the compiler suppresses the assignment operator for such class.
Compiler generates a similar warning (#2266 - /en-us/articles/cdiag2266 ) if class has const member.
Compiler encounters code in which one entity is hidden by another, this results in being no use of first entity.
The following sample generates Warning 1125 :
Cause:
A virtual function cannot be a static member, since a virtual function call relies on a specific object (base or derived) for determining which function to invoke (note: ISO C++ standard); whereas Static functions are object independent.
Default type of this diagnostic is warning. (Microsoft* Visual C++*'s equivalent warning is C4526.)
Example:
Cause:
Compiler generates default assignment operator and copy constructor for class that does not define one. It is member-wise copy of the data members of an object. As const data members cannot be modified once initialized, the assignment operator generated for such class would be invalid. So the compiler suppresses the assignment operator and copy constructor for such class.
Compiler generates a similar warning (#2267- /en-us/articles/cdiag2267 ) if class has reference member.
