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Q168934: FIX: Multiple Errors Compiling Std C++ Library Headers with /Za

Article: Q168934
Product(s): Microsoft C Compiler
Version(s): 5.0,6.0
Operating System(s): 
Keyword(s): kbtool kbCompiler kbCPPonly kbLangCPP kbVC kbVC500bug kbVC600bug kbNoUpdate
Last Modified: 10-FEB-2002

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The information in this article applies to:

- The Standard C++ Library, used with:
   - Microsoft Visual C++, 32-bit Enterprise Edition, versions 5.0, 6.0 
   - Microsoft Visual C++, 32-bit Professional Edition, versions 5.0, 6.0 
   - Microsoft Visual C++, 32-bit Learning Edition, version 6.0 
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SYMPTOMS
========

If you use the /Za switch (Disable Language Extensions) when compiling the
Standard C++ Library headers, it causes multiple compiler errors. For example:

  cl /Za /c /GX /Tp"iosfwd"

Causes the following compiler errors:

  iosfwd(132) : error C2906: C++ language change: to explicitly specialize
  class template 'char_traits' use the following syntax - template<>
  struct char_traits<unsigned short> ...

  iosfwd(171) : error C2906: C++ language change: to explicitly specialize class
  template 'char_traits' use the following syntax - template<> struct
  char_traits<char> ...

Examples of other header files known to cause multiple compiler errors like
C2838, C2146, and C2501 are: <utility>, <iterator>, <xstring>,
<functional>, and <limits>.

RESOLUTION
==========

Do not use the compiler option /Za (Disable Language Extensions) when compiling
the Standard C++ Library headers.

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 Microsoft Visual C++ .NET.

Additional query words:

======================================================================
Keywords          : kbtool kbCompiler kbCPPonly kbLangCPP kbVC kbVC500bug kbVC600bug kbNoUpdate 
Technology        : kbVCsearch kbAudDeveloper kbVCLibrary
Version           : :5.0,6.0
Issue type        : kbbug
Solution Type     : kbfix

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