Article: Q121888
Product(s): Microsoft C Compiler
Version(s): 1.0,1.5,2.0,4.0,4.1,4.2,5.0,6.0
Operating System(s):
Keyword(s): kbCompiler kbCPPonly kbVC kbVC100 kbVC150 kbVC200 kbVC400 kbVC410 kbVC420 kbVC500 kbVC6
Last Modified: 11-FEB-2002
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The information in this article applies to:
- Microsoft Visual C++, versions 1.0, 1.5, 2.0, 4.0, 4.1
- Microsoft Visual C++, 32-bit Enterprise Edition, versions 4.2, 5.0, 6.0
- Microsoft Visual C++, 32-bit Professional Edition, versions 4.2, 5.0, 6.0
- Microsoft Visual C++, 32-bit Learning Edition, version 6.0
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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
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Keywords : kbCompiler kbCPPonly kbVC kbVC100 kbVC150 kbVC200 kbVC400 kbVC410 kbVC420 kbVC500 kbVC600
Technology : kbVCsearch kbVC400 kbAudDeveloper kbvc150 kbvc100 kbVC410 kbVC420 kbVC500 kbVC600 kbVC200 kbVC32bitSearch kbVC500Search
Version : :1.0,1.5,2.0,4.0,4.1,4.2,5.0,6.0
Issue type : kbprb
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