Re: [boost] The noexcept Specifier & Block

Subject: Re: [boost] The noexcept Specifier & Block
From: Peter Dimov (pdimov_at_[hidden])
Date: 2009-04-17 16:39:18

Alexander Terekhov:

> Avoiding unwinding for unexpected exceptions, for example.

The reason the standard specifies calling unexpected() at the exception spec 
point is conceptually sound (but practically not that useful). Consider

void f()
{
    throw X();
}

void g() throw(Y)
{
    f();
}

void h() throw(Z)
{
    g();
}

If unexpected() is always invoked at the throw point, there is no way for an 
exception to escape this call stack. If it's invoked at the exception 
specification points, it can, in principle, first throw a Y, then a Z. The 
primary purpose of unexpected(), as originally envisaged (I presume), is 
exception translation.