Synopsis

(Required) The validity of values passed to library functions shall be checked (!=0 case).

Enabled by default

Yes

Severity/Certainty

Medium/Medium

Full description

A parameter value (==0) might cause a domain or range error. This check is identical to MISRAC2004-20.3_c.

Coding standards

Code examples

The following code example fails the check and will give a warning:

#include <math.h>

void nez(double d1, double d2) {
  double e;
  e = fmod(1, 0.0);      /* const not in range */
  e = fmod(1, d1);     /* var not checked */
  if(d1 != 0) {
  } else {
    e = fmod(1, d1);   /* checked but in wrong branch */
  }
  if(d1 != 0) {
    d1 = d2;
    e = fmod(1, d1);   /* checked but updated */
  }
}

The following code example passes the check and will not give a warning about this issue:

#include <math.h>

void example(double d) {
  double e;
  if(d != 0) {
    e = logb(d); /* checked before use */
  }
  if(0 != d) {
    e = logb(d); /* checked before use */
  }
  if(d == 0) {
  } else {
    e = logb(d); /* checked before use */
  }
  if(0 == d) {
  } else {
    e = logb(d); /* checked before use */
  }
  e = logb(1.0); /* constant != 0 */
}