Find something wrong in this description?  Help us fix it! 
Onex Reno BlackNavyTan Reno Onex Onex BlackNavyTan F6v5Sqz Onex Reno BlackNavyTan Reno Onex Onex BlackNavyTan F6v5Sqz Onex Reno BlackNavyTan Reno Onex Onex BlackNavyTan F6v5Sqz Onex Reno BlackNavyTan Reno Onex Onex BlackNavyTan F6v5Sqz Onex Reno BlackNavyTan Reno Onex Onex BlackNavyTan F6v5Sqz Onex Reno BlackNavyTan Reno Onex Onex BlackNavyTan F6v5Sqz

Why does PolySpace 5.1.1 (R2008a) show a red non-terminating loop (NTL) check in my code?

Onex Reno BlackNavyTan Reno Onex Onex BlackNavyTan F6v5Sqz

Asked by MathWorks Support Team
on 27 Jun 2009

My C code looks as follows. When I run a PolySpace verification, the "for" keyword that is mentioned in the comments is marked red with a message that the loop never terminates. Also, I get another red check for a underflow error. I am using the option "-detect-unsigned-overflows".

int main () {
    int intC;
    unsigned int uintA, uintB, i = 0;
    uintA = 20;
    uintB = 30;
    intC = 10;
    // The following keyword "for" is marked with
    // a red NTL check.
    for(i; i < 10; i++) {
      // Subtraction marked with a red UNFL check
      // for a possible underflow.
      if ((uintA - uintB) < uintC) { // UNFL: 20 - 30
        //...
      }
    }
}

Tags

No tags entered yet.

Reno Reno Onex Onex Onex BlackNavyTan BlackNavyTan
BlackDenimSmoke BlackDenimSmoke Shark Shark Footwear Footwear Footwear Klogs Shark Klogs Shark Klogs Footwear BlackDenimSmoke Klogs 4Aq08

1 Answer

Answer by MathWorks Support Team BlackNavyTan Onex Onex Reno Onex BlackNavyTan Reno on 27 Jun 2009
  Accepted Answer

The red NTL check is caused by the red underflow check (UNFL) within the loop. Correcting the code that causes the UNFL check or removing the option "-detect-unsigned-overflows" will cause the NTL check to disappear.

  0 Comments

Sign in to comment.