Re: Why does std::stack::pop() not throw an exception if the stack is empty?

From:

James Kanze <james.kanze@gmail.com>

Newsgroups:

comp.lang.c++

Date:

Fri, 4 Feb 2011 09:36:20 -0800 (PST)

Message-ID:

<1db175e2-d5de-4e5e-84d2-f80cf263c8dd@h19g2000prh.googlegroups.com>

On Feb 3, 9:51 pm, Debajit Adhikary <debaj...@gmail.com> wrote:

Why does std::stack::pop() not throw an exception if the stack
is empty and there is nothing to pop?

(I'm designing a specialized Stack for my own code and would
like to know the tradeoffs with this approach (which requires
one to manually check if the stack is empty vs. throwing an
exception.

My guess here would be that although C++ supports
exception-handling, it comes with a small runtime overhead,
and therefore, for maximum performance, the decision was made
not to throw an exception in std::stack::pop).

I doubt that performance had much to do with it. Popping an
empty stack is a programming error; programming errors shouldn't
trigger exceptions, but rather immediate termination of the
process.

The tradition in C++ is to not require checking such programming
errors, and to leave them as undefined behavior. A good
implementation can then check, and then abort, in debugging
mode; if the check may be too expensive, it can also turn it off
in optimizing mode, and still be conforming.

--
James Kanze