DOCUMENT:Q235601  11-FEB-2002  [visualc]
TITLE   :FIX: Putenv() Function Causes Memory Leak
PRODUCT :Microsoft C Compiler
PROD/VER::4.0,4.1,4.2,5.0,6.0
OPER/SYS:
KEYWORDS:kbCRT kbVC500bug kbVC600bug kbDSupport kbGrpDSVCCompiler kbNoUpdate

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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

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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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