Microsoft KB Archive/164150

= DOC: C4237 Online Help Contains Wrong Information on "bool" =

Article ID: 164150

Article Last Modified on 10/24/2003

-

APPLIES TO


 * Microsoft Visual C++ 4.2 Enterprise Edition
 * Microsoft Visual C++ 4.2 Professional Edition

-



This article was previously published under Q164150



SUMMARY
The online help on C4237 in Visual C++ 4.2 states that the keywords bool, true, false, mutable, explicit, and typename are for future use. The last paragraph states the following:

If you include the header OAIDL.H, note that this header defines both bool and boolval. To avoid this warning and prevent possible compatibility problems with future versions of Visual C++, your code should use the boolval definition instead of the bool definition.

This information is incorrect. If you use OAIDL.H for bool keyword, the following error message appears:

error C2065: 'bool' : undeclared identifier



MORE INFORMATION
In Visual C++ 4.2, the keywords bool, true, and false are declared in the header file yvals.h. By including this file in your program, you can use the keywords bool, true, and false. Since the standard C++ header files (that is, iostream, ostream, etc.) automatically include yvals.h, if you use any of these header files you can use bool, true, and false. If you are also including windows.h, then make sure that windows.h is included above yvals.h or the standard C++ header files, otherwise the C4237 warning appears. This happens because yvals.h disables the C4237 warning with a #pragma statement.

The following programs compile without errors in Visual C++ 4.2.

Sample Code
/* Compile options needed:none */

#include   #include

void main(void){ bool x;  BOOL Y;

x=true; Y=FALSE;

}

Or,

#include   #include 

void main(void){ bool x;  BOOL Y;

x=true; Y=FALSE;

}

Additional query words: bool kbOLDocs kbCompiler kbVC420 kbVC500fix kbDSupport kbdss

Keywords: kbdocfix kbdocerr kbcode KB164150

-

[mailto:TECHNET@MICROSOFT.COM Send feedback to Microsoft]

© Microsoft Corporation. All rights reserved.