exception specification

< cpp‎ | language

Lists the exceptions that a function might directly or indirectly throw.


[edit] Syntax

throw(typeid, typeid, ...) (deprecated)

[edit] Explanation

If a function is declared with type T listed in its exception specification, the function may throw exceptions of that type or a type derived from it.

If the function throws an exception of the type not listed in its exception specification, the function std::unexpected is called. The default function calls std::terminate, but it may be replaced by a user-provided function (via std::set_unexpected) which may call std::terminate or throw an exception. If the exception thrown from std::unexpected is accepted by the exception specification, stack unwinding continues as usual. If it isn't, but std::bad_exception is allowed by the exception specification, std::bad_exception is thrown. Otherwise, std::terminate is called.

[edit] Example

class X {};
class Y {};
class Z : public X {};
class W {};
void f() throw(X, Y) 
    int n = 0;
    if (n) throw X(); // OK
    if (n) throw Z(); // also OK
    throw W(); // will call std::unexpected()

[edit] See also