Catching by value¶
ID: cpp/catch-by-valueKind: problemSecurity severity: Severity: warningPrecision: very-highTags: - efficiency - correctness - exceptionsQuery suites: - cpp-security-and-quality.qls
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Catching an exception by value will create a new local variable which is a copy of the originally thrown object. Creating the copy is slightly wasteful, but not catastrophic. More worrisome is the fact that if the type being caught is a strict supertype of the originally thrown type, then the copy might not contain as much information as the original exception.
Recommendation¶
The parameter to thecatch block should have its type changed fromT toT& orconstT&.
Example¶
voidbad(){try{/* ... */}catch(std::exceptiona_copy_of_the_thrown_exception){// Do something with a_copy_of_the_thrown_exception}}voidgood(){try{/* ... */}catch(conststd::exception&the_thrown_exception){// Do something with the_thrown_exception}}
References¶
C++ FAQ: What should I throw?, What should I catch?.
Wikibooks: Throwing objects.