Yes, sorry. h(g(f(x))) was not meant as a C++ expression, but how the function call each other.

In full notation it would be:

// f throws an exception

int f(int x) {

    throw std::exception();

    return x * x;

}

// g does not have to care

int g(int x) {

    return 4 * f(x);

}

// h catches the exception

int h(int x) {

    try {

        int y = g(x);

    } catch(const std::exception& e)

    {

        // handle it 

    }

    return y + 2;

}

-----Ursprüngliche Nachricht-----
Von: Rainer Deyke via Std-Proposals <std-proposals@lists.isocpp.org>
Gesendet: Fr 28.08.2026 14:16
Betreff: Re: [std-proposals] fine-control exception/error/UB handling on function boundary
An: std-proposals@lists.isocpp.org;
CC: Rainer Deyke <rainerd@eldwood.com>;


On 8/28/26 12:08, Sebastian Wittmeier via Std-Proposals wrote:
> h(g(f()))
>
>  
> One important philosophy of exceptions is that code in-between - like the function g - does not have to care, what kind of exceptions are thrown by f, as long as h handles it.

Neither g nor h will ever see the exception if f throws.  Neither g nor
h have the opportunity to handle the exception.  Neither g nor h will
even be called.


--
Rainer Deyke - rainerd@eldwood.com

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