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Invalid use of standard library integer routine

Wrong arguments to standard library function

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Description

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

  • Character conversion functions (toupper(), tolower(), and so on)

  • Character check functions (isalnum(), isalpha(), iscntrl(), isdigit, and so on)

  • Integer division functions (div(), ldiv(), and so on)

  • Absolute value functions (abs(), labs(), and so on)

Fix

The fix depends on the root cause of the defect. Often the result details (or source code tooltips in Polyspace as You Code) 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 this event history, you can search for previous references of variables relevant to the defect using right-click options in the source code and find related events. See also Interpret Bug Finder Results in Polyspace Desktop User Interface or Interpret Bug Finder Results in Polyspace Access Web Interface (Polyspace Access).

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:

Extend Checker

Extend this checker to check for defects caused by specific values and invalid use of functions from a custom library. For instance:

Examples

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#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

Version History

Introduced in R2013b

See Also

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