Q168440: FIX: Stream Operator << Cannot Handle __int64 Type

Article: Q168440
Product(s): Microsoft C Compiler
Version(s): 5.0,6.0
Operating System(s): 
Keyword(s): kberrmsg kbCRT kbVC kbVC500bug kbVC600bug kbNoUpdatekbbuglist
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 try to pass an __int64 variable to the ostream operator <<, you get
the following error:

  error C2593: 'operator <<' is ambiguous

CAUSE
=====

There is no operator << for __int64 type defined for the ostream class.

RESOLUTION
==========

Define your own version of operator <<. The following sample code section
shows a simple solution for << operator that converts the __int64 variable
to a char * type and passes it to the ostream << operator.

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.

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

The following sample program demonstrates the problem and workaround:

  //Sample.cpp
  // Compiler Options : /GX

  //#define WORKAROUND   //Uncomment this line to workaround

  #include<iostream>
  using namespace std;

  #ifdef WORKAROUND
  std::ostream& operator<<(std::ostream& os, __int64 i )
  {
      char buf[20];
      sprintf(buf,"%I64d", i );
      os << buf;
      return os;
  }

  #endif

  int main(){
  __int64  i64;

  cout << i64 ;

  return 0;
  }

Additional query words:

======================================================================
Keywords          : kberrmsg kbCRT kbVC kbVC500bug kbVC600bug kbNoUpdate kbbuglist
Technology        : kbVCsearch kbAudDeveloper kbVCLibrary
Version           : :5.0,6.0
Issue type        : kbbug
Solution Type     : kbfix

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