MISRA C++:2008 Rule 4-10-2

Literal zero (0) shall not be used as the null-pointer-constant

Description

Rule Definition

Literal zero (0) shall not be used as the null-pointer-constant.¹

Rationale

In C++, you can use the literals 0 and NULL as both an integer and a null pointer constant. However, use of 0 as a null pointer constant or NULL as an integer can cause developer confusion.

This rule restricts the use of the literal 0 to integers. MISRA C++:2008 Rule 4-10-1 restricts the use of NULL to null pointer constants.

Polyspace Implementation

The checker flags assignment of 0 to a pointer variable or binary operations involving 0 and a pointer. Assignments can be direct or indirect such as passing 0 as pointer argument to a function.

Troubleshooting

If you expect a rule violation but Polyspace^® does not report it, see Diagnose Why Coding Standard Violations Do Not Appear as Expected.

Examples

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Compliant and Noncompliant Uses of Literal 0

#include <cstddef>

void checkInteger(int);
void checkPointer(int *);

void main() {
    checkInteger(0); //Compliant
    checkPointer(0); //Noncompliant
}

In this example, the use of 0 as argument to the checkPointer function is noncompliant because the function expects an int * argument.

Check Information

Group: Standard Conversions

Category: Required

Version History

Introduced in R2018a