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DCL01-C-EX2: A temporary variable within a new scope inside of a macro can override a surrounding identifier.override an identifier in a containing scope. However,this exception does not apply to to the arguments of the macro itself.
| Code Block | ||||
|---|---|---|---|---|
| ||||
#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.
Recommendation | Severity | Likelihood | Remediation Cost | Priority | Level |
|---|---|---|---|---|---|
DCL01-C | Low | Unlikely | Medium | P2 | L3 |
Automated Detection
Tool | Version | Checker | Description | ||||||
|---|---|---|---|---|---|---|---|---|---|
| Astrée |
| Supported indirectly via MISRA C:2012 Rule 5.3. | |||||||
| Axivion Bauhaus Suite |
| CertC-DCL01 | |||||||
| CodeSonar |
| LANG.ID.ND.NEST | Non-distinct identifiers: nested scope | ||||||
| Compass/ROSE |
| CC2.DCL01 | Fully implemented | |||||||
| Helix QAC |
| C0795, C0796, C2547, C3334 | |||||||
| Klocwork |
| MISRA.VAR.HIDDEN |
| LDRA tool suite |
| 131 S | Fully implemented | ||||||
| Parasoft C/C++test |
Variable hides another variable of same name with nested scope
| CERT_C-DCL01-a | Identifier declared in a local or function prototype scope shall not hide an identifier declared in a global or namespace scope | |||||||
| PC-lint Plus |
| 578 | Fully supported | ||||||
| Polyspace Bug Finder |
| Checks for variable shadowing (rule fully covered) | |||||||
| PVS-Studio |
| V561, V688, V703, V711, V2015 | |||||||
| RuleChecker |
| Supported indirectly via MISRA C:2012 Rule 5.3. |
2547
3334
| Splint |
|
Related Vulnerabilities
Search for vulnerabilities resulting from the violation of this rule on the CERT website.
Related Guidelines
| SEI CERT C++ Coding Standard | VOID DCL01-CPP. Do not reuse variable names in subscopes |
| MISRA C:2012 | Rule 5.3 (required) |
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