FIX: Operator ++ In Return Statement May Cause Access Violation

This article was previously published under Q205681
This article has been archived. It is offered "as is" and will no longer be updated.
SYMPTOMS
A compiled program may cause access violation if it contains a function returning a struct by value, and the return expression has either a postfix increment or decrement operator.
RESOLUTION
There following are workarounds for this problem.
  1. Remove the postfix increment/decrement operator from the return expression.
  2. Use the prefix increment/decrement operator.
STATUS
Microsoft has confirmed that this is a bug in the Microsoft products that are listed at the beginning of this article.

This bug was corrected in Visual Studio 6.0 Service Pack 3. For more information about Visual Studio service packs, please see the following articles in the Microsoft Knowledge Base:
194022 INFO: Visual Studio 6.0 Service Packs, What, Where, Why

194295 HOWTO: Tell That Visual Studio 6.0 Service Packs Are Installed
MORE INFORMATION
To reproduce the problem, build and run the following sample program.
Sample----------------#include <stdio.h>#include <stdlib.h>typedef struct{ int   type; int   offset;}ST;int i;struct{ ST  *tab;    int used;  }STAdmin;ST MyFunction (){#ifdef WORKAROUND_1   int temp = i++;   return STAdmin.tab[temp];#endif#ifdef WORKAROUND_2   return STAdmin.tab[++i - 1];#endif<BR/>   return STAdmin.tab[i++];}void main(void){   ST a;   int i;   STAdmin.tab = (ST*) malloc(sizeof(ST)*10);   STAdmin.used = 0;   // Initialize the Array    for(i=0;i<10;i++)   {       STAdmin.tab[i].offset=i;       printf("%d\n",STAdmin.tab[i].offset);   }   // Read in the Array    for(i=0;i<10;i++)   {	a = MyFunction();	printf("%d\n",a.offset);   }}// End of Sample Code				
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Properties

Article ID: 205681 - Last Review: 02/23/2014 01:13:11 - Revision: 2.0

  • Microsoft Visual C++ 6.0 Enterprise Edition
  • Microsoft Visual C++ 6.0 Professional Edition
  • Microsoft Visual C++, 32-bit Learning Edition 6.0
  • kbnosurvey kbarchive kbbug kbfix kbvs600sp3fix KB205681
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