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This compliant solution complies with MEM31 MEM51-CPP. Properly deallocate dynamically allocated resources, however, while handling resource cleanup in catch clauses does work, it can have several disadvantages:
...
A better approach would be to employ RAII. This forces every object to 'clean up after itself' in the face of abnormal behavior, preventing the programmer from having to do so. This approach additionally benefits by not requiring statements to handle resource allocation errors in conformance with MEM32MEM52-CPP. Detect and handle memory allocation errors.
| Code Block | ||||
|---|---|---|---|---|
| ||||
struct SomeType {
void processItem() noexcept(false);
};
void f() {
SomeType st;
try {
st.processItem();
} catch (...) {
// Handle error
throw;
}
}
|
...
This compliant solution utilizies std::unique_ptr to create objects that clean up after themselves should anything go wrong in the C::C() constructor. See VOID MEM00-CPP. Don't use auto_ptr where copy semantics might be expected for more information on std::unique_ptr.
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Rule | Severity | Likelihood | Remediation Cost | Priority | Level |
|---|---|---|---|---|---|
MEM44ERR40-CPP | Low | Probable | High | P2 | L3 |
Automated Detection
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Related Guidelines
| CERT C++ Coding Standard | MEM32MEM52-CPP. Detect and handle memory allocation errors MEM31MEM51-CPP. Properly deallocate dynamically allocated resources |
Bibliography
| [ISO/IEC 14882-2014] | 15.2, "Constructors and Destructors" |
| [Meyers 96] | Item 9: "Use destructors to prevent resource leaks". |
| [Stroustrup 2001] | "Exception-Safe Implementation Techniques" |
| [Cline 2009] | 17.2, "I'm still not convinced: a 4-line code snippet shows that return-codes aren't any worse than exceptions; |
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