Find something wrong in this description?  Help us fix it! 
Volcom Tavira BlackTan Tavira Volcom BlackTan rqxFtprz Volcom Tavira BlackTan Tavira Volcom BlackTan rqxFtprz Volcom Tavira BlackTan Tavira Volcom BlackTan rqxFtprz Volcom Tavira BlackTan Tavira Volcom BlackTan rqxFtprz Volcom Tavira BlackTan Tavira Volcom BlackTan rqxFtprz Volcom Tavira BlackTan Tavira Volcom BlackTan rqxFtprz

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

Volcom Tavira BlackTan Tavira Volcom BlackTan rqxFtprz

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.

Volcom Tavira BlackTan Volcom Tavira BlackTan
BlackOlive Black Stacy Triolo Light BlackCognac StrawRed Adams BlueGray Blue BrownDark zzxS0qw

1 Answer

Answer by MathWorks Support Team BlackTan BlackTan Volcom Tavira Volcom Tavira 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.