Q66575: Multithreaded Version of strtok() in C 6.00 Can Cause GP Fault

Article: Q66575
Product(s): See article
Version(s): 6.00
Operating System(s): OS/2
Keyword(s): ENDUSER | buglist6.00 fixlist6.00a | mspl13_c
Last Modified: 21-JAN-1991

In certain cases, using the multithreaded version of the strtok()
function from Microsoft C version 6.00 can cause a General Protection
fault. This problem has been identified and corrected in the C version
6.00a maintenance release.

Sample Code
-----------

#define INCL_DOS
#include <os2.h>
#include <conio.h>
#include <process.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

void StartThread(char *pszFileName);
void ThreadProc(char *pszFileName);

void main(void)
 {
  StartThread("THREAD01.TXT");
  StartThread("THREAD02.TXT");
  StartThread("THREAD03.TXT");
  StartThread("THREAD04.TXT");
  StartThread("THREAD05.TXT");
  while(!kbhit());
 }

void StartThread(char *pszFileName)
 {
  int ThreadID;

  ThreadID = _beginthread(ThreadProc,
                           NULL,
                           8192,
                           pszFileName);
  if(ThreadID == -1)
             printf("Couldn't Start Thread for '%s'\n", pszFileName);
 }

void ThreadProc(char *pszFileName)
{
   FILE *Input, *Output;
   char Line[256], *t, OutFileName[16];

   Input = fopen(pszFileName, "rt");
   if(Input == NULL)
   {
      printf("%.3d: Error Opening Input File - '%s'\n",
                 *_threadid, pszFileName);
      _endthread();
   }
   sprintf(OutFileName, "THREAD%.2d.OUT", atoi(&pszFileName[6]));

   Output = fopen(OutFileName, "w");
   if(Output == NULL)
   {
      printf("%.3d: Error Opening Output File - '%s'\n",
                *_threadid, OutFileName);
      fclose(Input);
      _endthread();
   }
   while(fgets(Line, sizeof(Line), Input))
   {
      Line[strlen(Line)-1] = '\0';

      fprintf(Output, "%.3d: Input Line: '%s'\n", *_threadid, Line);

      for(t = strtok(Line, " \n\r");
           t != NULL; t = strtok(NULL, " \n\r"))
         fprintf(Output, "%.3d:  Token: '%s'\n", *_threadid, t);

      fprintf(Output, "\n");
   }
   fclose(Input);
   fprintf(Output, "\n%.3d: Going to sleep\n", *_threadid);
   fclose(Output);
   DosSleep(10000L);
   _endthread();
}

THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY NOT APPLY.

Copyright Microsoft Corporation 1986-2002.