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AUTOSAR C++14 Rule M0-2-1

An object shall not be assigned to an overlapping object

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Description

Rule Definition

An object shall not be assigned to an overlapping object.

Rationale

When you assign an object to another object with overlapping memory, the behavior is undefined.

The exceptions are:

  • You assign an object to another object with exactly overlapping memory and compatible type.

  • You copy one object to another with memmove.

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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void func (void) {
    union {
        short i;
        int j;
    } a = {0}, b = {1};
    
    a.j = a.i;   //Noncompliant
    a = b;       //Compliant
}

In this example, the rule is violated when a.i is assigned to a.j because the two variables have overlapping regions of memory.

Check Information

Group: Language Independent Issues
Category: Required, Automated

Version History

Introduced in R2019a

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See Also

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