Main Content

MISRA C++:2008 Rule 4-10-1

NULL shall not be used as an integer value

expand all in page

Description

Rule Definition

NULL shall not be used as an integer value.

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 NULL to null pointer constants. MISRA C++:2008 Rule 4-10-2 restricts the use of the literal 0 to integers.

Polyspace Implementation

The checker flags assignment of NULL to an integer variable or binary operations involving NULL and an integer. Assignments can be direct or indirect such as passing NULL as integer 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

expand all

#include <cstddef>

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

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

In this example, the use of NULL as argument to the checkInteger function is noncompliant because the function expects an int argument.

Check Information

Group: Standard Conversions
Category: Required

Version History

Introduced in R2018a

See Also

Topics