Article ID: 121888
Article Last Modified on 12/1/2003
APPLIES TO
- Microsoft Visual C++ 1.0 Professional Edition
- Microsoft Visual C++ 1.5 Professional Edition
- Microsoft Visual C++ 2.0 Professional Edition
- Microsoft Visual C++ 4.0 Standard Edition
- Microsoft Visual C++ 4.1 Subscription
- Microsoft Visual C++ 4.2 Enterprise Edition
- Microsoft Visual C++ 5.0 Enterprise Edition
- Microsoft Visual C++ 6.0 Enterprise Edition
- Microsoft Visual C++ 4.2 Professional Edition
- Microsoft Visual C++ 5.0 Professional Edition
- Microsoft Visual C++ 6.0 Professional Edition
- Microsoft Visual C++ 6.0 Standard Edition
This article was previously published under Q121888
SYMPTOMS
If an object is used to initialize an embedded structure, the compiler produces error C2440: 'initializing': cannot convert from '<type1> ' to '<type2> '.
CAUSE
This behavior is by design. Although an aggregate that is a class may be initialized with an object of its class, there is not a similar provision for subaggregates.
RESOLUTION
To work around this behavior, use a member by member initialization.
MORE INFORMATION
The following sample code demonstrates this problem and its resolution. The error produced in the initialization of two2 is error C2440: 'initializing' : cannot convert from 'struct ::One ' to 'int '.
Sample Code
/* Compile options needed: none
*/
struct One
{
int i;
};
struct Two
{
int j;
One one;
int k;
};
One one1 = { 3 }; // Initialize structure member - OK
One one2 = one1; // Initialize structure - OK
Two two1 = { 1, one1, 3 }; // Error, can not initialize subaggregate
Two two2 = { 1, one1.i, 3 }; // Member by member initialization - OK
Additional query words: 8.00 8.00c 9.00 10.00 11.00
Keywords: kbprb kbcpponly kbcompiler KB121888
