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Q235601: FIX: Putenv() Function Causes Memory Leak

Article: Q235601
Product(s): Microsoft C Compiler
Version(s): 4.0,4.1,4.2,5.0,6.0
Operating System(s): 
Keyword(s): kbCRT kbVC500bug kbVC600bug kbDSupport kbGrpDSVCCompiler kbNoUpdate
Last Modified: 11-FEB-2002

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The information in this article applies to:

- Microsoft Visual C++, versions 4.0, 4.1 
- Microsoft Visual C++, 32-bit Enterprise Edition, versions 4.2, 5.0, 6.0 
- Microsoft Visual C++, 32-bit Professional Edition, versions 4.2, 5.0, 6.0 
- Microsoft Visual C++, 32-bit Learning Edition, version 6.0 
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SYMPTOMS
========

A memory leak results from calls to putenv in the following circumstances:

- An environment variable is removed.

- An environment variable is replaced.

- The input parameter does not contain an equal sign (=) character.

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

Steps to Reproduce Behavior
---------------------------

The following sample code demonstrates the types of calls that will cause a
memory leak.

  #include <stdlib.h>

  void main()
  {
      for (;;) {

          putenv( "MYVAR1=mystring" ); // Replaces string MYVAR1
                                       // after first iteration.

          putenv( "MYVAR2=mystring" ); // Creates and removes MYVAR2.
          putenv( "MYVAR2=" );         // 

          putenv( "MYVAR3" );          // Invalid string missing "=".
      }
  }

Additional query words: kbvc400

======================================================================
Keywords          : kbCRT kbVC500bug kbVC600bug kbDSupport kbGrpDSVCCompiler kbNoUpdate 
Technology        : kbVCsearch kbVC400 kbAudDeveloper kbVC410 kbVC420 kbVC500 kbVC600 kbVC32bitSearch kbVC500Search
Version           : :4.0,4.1,4.2,5.0,6.0
Issue type        : kbbug
Solution Type     : kbfix

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