What requirements does the standard place upon a type thrown in an exception?

Question

I thought exceptions imposed a bit more on the thrown type than the standard actually imposes. I want to clear up this confusion. What is actually imposed on those types?

templatetypedef · Accepted Answer · 2011-07-28T19:46:25.823

4

The C++ ISO spec, §15.1/3, states that

The type of the throw-expression shall not be an incomplete type, or a pointer or reference to an incomplete type, other than void*, const void*, volatile void*, or const volatile void*. Except for these restrictions and the restrictions on type matching mentioned in 15.3, the operand of throw is treated exactly as a function argument in a call (5.2.2) or the operand of a return statement.

From this, it seems that you should be able to throw anything you'd like, as long as you're not throwing a type that you've only forward-declared.

EDIT: As @Billy ONeal points out, the type must be copyable, which means that it should support a copy constructor.

edited Jul 28 '11 at 19:46

answered Jul 28 '11 at 19:18

templatetypedef

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I think it needs a copy constructor anyway, given 15.1 paragraph 3 `A throw-expression initializes a temporary object, called the exception object` – Billy ONeal Jul 28 '11 at 19:44
@Billy ONeal- Thanks for pointing that out! I'll update my answer. – templatetypedef Jul 28 '11 at 19:46

What requirements does the standard place upon a type thrown in an exception?

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