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DCL01-C-EX2: A temporary variable within a new scope inside of a macro can override an identifier in a containing scope. This However,this exception does not apply to to the arguments of the macro itself.
| Code Block | ||||
|---|---|---|---|---|
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#define SWAP(type, a, b) do { type tmp = a; a = b; b = tmp; } while(0)
void func(void) {
int tmp = 100;
int a = 10, b = 20;
SWAP(int, a, b); /* Hidden redeclaration of tmp is acceptable */
SWAP(int, tmp, b); /* NONCOMPLIANT: Hidden redeclaration of tmp clashes with argument */
} |
Risk Assessment
Reusing a variable name in a subscope can lead to unintentionally referencing an incorrect variable.
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