When an exception is thrown, the exception object operand of the throw expression is copied into a temporary object that is used to initialize the handler. The C++ Standard, [except.throw], paragraph 3 [ISO/IEC 14882-2014], states in part:
Throwing an exception copy-initializes a temporary object, called the exception object. The temporary is an lvalue and is used to initialize the variable declared in the matching handler.
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Bibliography
| [Hinnant 2015] | |
| [ISO/IEC 14882-2014] | Subclause 15.1, "Throwing an Exception" |
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