Q100539: FIX: No C4051 Warnings Compiling .CPP or .CXX Files

Article: Q100539
Product(s): Microsoft C Compiler
Version(s): 7.00 | 1.00 1.50 | 1.00
Operating System(s): 
Keyword(s): kbCompiler kbCPPonly kbVCkbbuglist kbfixlist
Last Modified: 26-JUL-2001

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The information in this article applies to:

- The C/C++ Compiler (CL.EXE), included with:
   - Microsoft C/C++ for MS-DOS, version 7.0 
   - Microsoft Visual C++ for Windows, 16-bit edition, versions 1.0, 1.5 
   - Microsoft Visual C++, 32-bit Editions, version 1.0 
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SYMPTOMS
========

When Microsoft C/C++ compiles a source code file that has the .CPP or .CXX
filename extension, the compiler does not generate any C4051 warning messages.
However, when Microsoft C/C++ compiles a source code file that contains similar
code but that has the .C filename extension, the compiler correctly generates
C4051 warning messages as follows:

  C4051: type conversion; possible loss of data

STATUS
======

Microsoft has confirmed this to be a bug in the Microsoft products listed at the
beginning of this article. This problem was corrected in Visual C++ 32-bit
Edition version 2.0.

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

According to the online help, the C4051 warning indicates that two data items in
an expression have different base types. In the process of converting one of the
items, it was truncated. To avoid this warning, cast the data item to an
appropriate data type.

The following code example demonstrates this problem.

Sample Code
-----------

  /*
   * Compile options needed: /W4
   */ 

  void main()
  {
     int i;

     i = 66.66 * 55.55;
  }

Additional query words: 1.00 1.50 7.00 8.00 8.00c

======================================================================
Keywords          : kbCompiler kbCPPonly kbVC kbbuglist kbfixlist
Technology        : kbVCsearch kbAudDeveloper kbCVCComp
Version           : 7.00 | 1.00 1.50 | 1.00
Issue type        : kbbug
Solution Type     : kbfix

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