Invalid use of standard library integer routine

Wrong arguments to standard library function

Description

This defect occurs when you use invalid arguments with an integer function from the standard library. This defect picks up:

• Character Conversion

  toupper, tolower

• Character Checks

  isalnum, isalpha, iscntrl, isdigit, isgraph, islower, isprint, ispunct, isspace, isupper, isxdigit

• Integer Division

  div, ldiv

• Absolute Values

  abs, labs

Fix

The fix depends on the root cause of the defect. Often the result details show a sequence of events that led to the defect. You can implement the fix on any event in the sequence. If the result details do not show the event history, you can trace back using right-click options in the source code and see previous related events. See also Interpret Bug Finder Results in Polyspace Desktop User Interface.

See examples of fixes below.

If you do not want to fix the issue, add comments to your result or code to avoid another review. See Address Polyspace Results Through Bug Fixes or Justifications.

Examples

Absolute Value of Large Negative

#include <limits.h>
#include <stdlib.h>

int absoluteValue(void) {

    int neg = INT_MIN;
    return abs(neg);
}

The input value to abs is INT_MIN. The absolute value of INT_MIN is INT_MAX+1. This number cannot be represented by the type int.

Correction — Change Input Argument

One possible correction is to change the input value to fit returned data type. In this example, change the input value to INT_MIN+1.

#include <limits.h>
#include <stdlib.h>

int absoluteValue(void) {

    int neg = INT_MIN+1;
    return abs(neg);
}

Result Information

Group: Numerical

Language: C | C++

Default: On

Command-Line Syntax: INT_STD_LIB

Impact: High

CWE ID: 227, 369, 682, 872