Article: Q93401
Product(s): Microsoft C Compiler
Version(s): 1.0,1.5,1.51,1.52,2.0,2.1,4.0,4.1,4.2,5.0,6.0
Operating System(s):
Keyword(s): kbCompiler kbCPPonly kbVC100 kbVC150 kbVC151 kbVC152 kbVC200 kbVC210 kbVC400 kbVC410 kb
Last Modified: 17-APR-2002
-------------------------------------------------------------------------------
The information in this article applies to:
- Microsoft C/C++ for MS-DOS
- Microsoft Visual C++ for Windows, 16-bit edition, versions 1.0, 1.5, 1.51, 1.52
- Microsoft Visual C++, 32-bit Editions, versions 1.0, 2.0, 2.1, 4.0, 4.1, 4.2, 5.0, 6.0
- Microsoft Visual C++.NET (2002)
-------------------------------------------------------------------------------
SYMPTOMS
========
When Microsoft C/C++ compiles an application that specifies a structure in the
default arguments for a function, the compilation fails with the following error
messages:
error C2059: syntax error : '{'
error C2279: cannot use braces to initialize default arguments
If you are using Visual C++ .NET compiler, the following compiler errors will be
generated instead of the above two compiler errors.
error C2143: syntax error : missing ')' before '{'
error C2059: syntax error : ')'
CAUSE
=====
According to the C++ grammar, the default value for an argument must be an
expression. An initializer list, such as that used to initialize a structure, is
not an expression.
RESOLUTION
==========
Define a constructor to perform the required initialization.
MORE INFORMATION
================
The first code example demonstrates the errors listed above. The second code
example demonstrates the correct method to initialize the structure.
Code Sample 1
-------------
/*
* Compile options needed: /c
*/
struct ag_type
{
int a;
float b;
};
void func(ag_type arg = {5, 7.0});
Code Sample 2
-------------
/*
* Compile options needed: /c
*/
struct ag_type
{
int a;
float b;
ag_type(int aa, float bb) : a(aa), b(bb) {}
};
void func(ag_type arg = ag_type(5, 7.0));
Additional query words: 8.00 8.00c 9.00 9.10
======================================================================
Keywords : kbCompiler kbCPPonly kbVC100 kbVC150 kbVC151 kbVC152 kbVC200 kbVC210 kbVC400 kbVC410 kbVC420 kbVC500 kbVC600
Technology : kbVCsearch kbVC400 kbAudDeveloper kbZNotKeyword8 kbvc150 kbvc100 kbZNotKeyword3 kbVC410 kbVC420 kbVC500 kbVC600 kbVC151 kbVC200 kbVC210 kbVC32bitSearch kbVC16bitSearch kbVC152 kbVCNET kbVC500Search
Version : :1.0,1.5,1.51,1.52,2.0,2.1,4.0,4.1,4.2,5.0,6.0
Issue type : kbprb
=============================================================================