Solving "RangeChecks instrumentation code detected an out of range array access"

[wavering]

Firstly, I am using Visual Studio 2013

I have a project written in VB6 and VC++ 6.0 which I am porting over to VB.NET and VC++.

Right at the heart of everything is a routine written in VC++ which runs to 1,400 lines of native code and processes a whole raft of arrays which are transferred from VB.NET. This routine may run for days during which time it literally runs through trillions of times (ie 10 ^ 12 ). If I split it into smaller routines there is a huge time penalty. Been there - tried that.

Amazingly, I have got this working in principle (I had expected to spend months debugging it but it worked almost immediately). One of the problems is/was that if you referred to a VB6 array in VC++ 6.0 you have to reverse it - so, for example

' VB6
Public dblObjectArrayGP(OBJECTS_MAX, PROPERTIES_MAX, TRIALS_MAX, STEPS_MAX) As Double

'In VC++ 6.0 refer to it as
dblObjectArrayGP[][TRIALS_MAX + 1][PROPERTIES_MAX + 1][OBJECTS_MAX + 1];

But it worked. Now in VB.NET - VC++ , Microsoft have arranged things so that you do NOT have to reverse arrays anymore. Which means that I have had to to reverse hundreds of array references (the law of unintended consequences). Hence my amazement when it worked in principle.

I have spelled all this out because I know that people will reply along the lines of:
"Why not write it all in VB.NET?"
"Why not break it into many smaller routines?"
"You should use Vectors not arrays" etc etc

and that is not helpful - this is a conversion job not a new project (if it were I would do lots of things differently). The original was written over 25 years and is at the limits of my ability to hold it together (ie it is hideously complicated). Original version(s) were written in QB4.5 and Quick C.

Now, when it runs maybe 50 times or so it fails and I get this message:

"Unhandled exception at 0x77B76767 (SafariPark.dll) in MOPEKS.exe: RangeChecks instrumentation code detected an out of range array access"

So, How do I find out which of my literally hundreds of array refences is causing this problem?

I have tried

try{

// Code here

}

catch(...){

// Breakpoint here
}

but it does not seem to get there, instead it stops in Microsoft Code as per this:

#if defined (_M_IX86)
    volatile ULONG dw[(sizeof(CONTEXT) + sizeof(EXCEPTION_RECORD))/sizeof(ULONG)];
#endif  /* defined (_M_IX86) */

#if defined (_M_IX86) || defined (_M_X64)
    if (IsProcessorFeaturePresent(PF_FASTFAIL_AVAILABLE))
#endif  /* defined (_M_IX86) || defined (_M_X64) */
        __fastfail(FailureCode);

#if defined (_M_IX86) || defined (_M_X64)

All help much appreciated!

[VictorN]

Now, when it runs maybe 50 times or so it fails and I get this message:

"Unhandled exception at 0x77B76767 (SafariPark.dll) in MOPEKS.exe: RangeChecks instrumentation code detected an out of range array access"

So, How do I find out which of my literally hundreds of array refences is causing this problem?

Did you debug your code?
What does the call stack show you when this "Unhandled exception ..." happens?

[VladimirF]

Whose message is that?
Google knows nothing about "RangeChecks instrumentation code detected an out of range array access"...
Is it produced by one of your AI modules?

[wavering]

Whose message is that?
Google knows nothing about "RangeChecks instrumentation code detected an out of range array access"...
Is it produced by one of your AI modules?

Well, there was one reference (in a foreign language) - now there are two! It is a standard Microsoft message - see screen shot below

What does the call stack show you when this "Unhandled exception ..." happens?

Jackpot! Thank you so much - this has totally solved the problem (which is in screenshot below but boiled down to this (which did NOT produce a warning error in VC++ 6.0 but should have)::

  char chrArray[40];  
  chrArray[40]='\0';   // Terminate the array (should be chrArray[39]='\0')

Yes, a silly error caused by confusing VB6 with VC++

So, how do you do that? Well, proceed as follows:

1. Turn on line numbers by

Tools --> Options --> Text Editor --> C/C++ --> General --> Line Numbers

2. Start debugging with F5 and stop on a breakpoint (important)

Debug --> Windows --> Call Stack

3. Click on error messsages (see screenshot below)

Now works OK ... thanks once again

[VictorN]

  char chrArray[40];  
  chrArray[40]='\0';   // Terminate the array (should be chrArray[39]='\0')

You could rewrite it in more simple manner as

  char chrArray[40] = {0};

[2kaud]

Another method of initializing an array to all 0 is

char chrArray[40] = {0};

Your code just sets the last element to 0 but IMO setting all elements like this is easier and safer!