KnowledgeBase Archive

An Archive of Early Microsoft KnowledgeBase Articles

View on GitHub

Q190965: PRB: IntelliSense Limitations with #define Macros

Article: Q190965
Product(s): Microsoft C Compiler
Version(s): WINNT:6.0
Operating System(s): 
Keyword(s): 
Last Modified: 17-JUL-2001

-------------------------------------------------------------------------------
The information in this article applies to:

- Microsoft Visual C++, 32-bit Enterprise Edition, version 6.0 
- Microsoft Visual C++, 32-bit Professional Edition, version 6.0 
- Microsoft Visual C++, 32-bit Learning Edition, version 6.0 
-------------------------------------------------------------------------------

SYMPTOMS
========

When working with macro definitions in Microsoft Visual C++, the following two
IntelliSense limitations occur:

- IntelliSense does not dynamically resolve macro definitions.

- Using #ifdef or #ifndef to define functions produces unexpected results.

STATUS
======

Microsoft is researching these problems and will post new information here in
the Microsoft Knowledge Base as it becomes available.

MORE INFORMATION
================

IntelliSense Does Not Dynamically Resolve Macro Definitions
-----------------------------------------------------------

Visual C++ 6.0 does not preprocess any macros while code is being edited. Because
of this, IntelliSense does not appear as it would if the macro were not used.
For example, the following TEST_FUNC macro aliases the Test() function:

     #define TEST_FUNC Test
     void Test(char *pszName);
     void Test(char *pszName){ printf("Name = %s", pszName); }

In another part of the code, typing "Test" followed by an open parenthesis
displays the Parameter Info ToolTip for the Test() function. However, typing
"TEST_FUNC" followed by an open parenthesis does not activate IntelliSense, even
though it will become the Test() function when it is compiled. This same
limitation applies to many other uses of macros, because IntelliSense does not
dynamically resolve macros to known identifiers.

This limitation can also cause problems with standard functions and structures.
Although most of the standard Win32 functions are handled properly, some header
files use macros to alias functions and structures. This can result in
IntelliSense not recognizing the macro. To verify whether this may be the cause
of the problem, search for the structure or function in the VC98\Include
directory. If the documented function or structure is actually a macro, this
could explain why IntelliSense is not recognizing it.


Using #ifdef or #ifndef to Define Functions Produces Unexpected Results
-----------------------------------------------------------------------

When functions are conditionally defined using #ifdef or #ifndef, IntelliSense
first determines whether the constant is defined in the project. If the macro is
defined, IntelliSense displays information on the correct function. If the macro
is undefined in the project, IntelliSense displays information for the first
function, regardless of whether #ifdef or #ifndef is used. IntelliSense can not
predict whether a constant will be defined, because constants can be set with
compiler switches. Do not depend on IntelliSense to always provide the
appropriate information when code is conditionally included in this way.


REFERENCES
==========

For additional information, please see the following article in the Microsoft
Knowledge Base:

  Q153284 Limitations of IntelliSense in Visual C++ 6.0

"About Automatic Statement Completion;" Visual C++ Documentation, Using Visual
C++, Visual C++ Users Guide, Text Editor, Overview: Text Editor, About Automatic
Statement Completion.

"Automatically Completing Statements;" Visual C++ Documentation, Using Visual
C++, Visual C++ Users Guide, Text Editor, How do I ... Topics: Text Editor,
Automatically completing Statements.

Additional query words: kbvc600

======================================================================
Keywords          :  
Technology        : kbVCsearch kbAudDeveloper kbVC600 kbVC32bitSearch
Version           : WINNT:6.0
Issue type        : kbprb

=============================================================================

THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY NOT APPLY.