compiler-warning-c4355.md

description	title	ms.date	f1_keywords	helpviewer_keywords
Learn more about: Compiler Warning (level 1 and level 4, off) C4355	Compiler Warning (level 1 and level 4, off) C4355	11/04/2016	C4355	C4355

Compiler Warning (level 1 and level 4, off) C4355

'this': used in base member initializer list

The this pointer is valid only within nonstatic member functions. It can't be used in the initializer list for a base class.

The base-class constructors and class member constructors are called before this constructor. This pattern is the same as passing a pointer to an unconstructed object to another constructor. If those other constructors access any members or call member functions on this, the result is undefined. You shouldn't use the this pointer until all construction is complete.

This warning is off by default. For more information, see Compiler Warnings That Are Off by Default.

The following sample generates C4355:

// C4355.cpp
// compile with: /w14355 /c
#include <tchar.h>

class CDerived;
class CBase {
public:
   CBase(CDerived *derived): m_pDerived(derived) {};
   ~CBase();
   virtual void function() = 0;

   CDerived * m_pDerived;
};

class CDerived : public CBase {
public:
   CDerived() : CBase(this) {};   // C4355 "this" used in derived c'tor
   virtual void function() {};
};

CBase::~CBase() {
   m_pDerived -> function();
}

int main() {
   CDerived myDerived;
}