Hi Matt,
>Just out of curiosity, what is the reasoning for this? Is this for g++
specifically, or C++ in general?
It's for C++ in general.
The rational (and experience) is that if someone puts a throw(something)
specification on a function or method, and that routine relies upon other
code, and that code is unspecified OR the throw specification changes AND
the unsuspecting dependent code with the throw specification or try/catch
wrapper is not updated when the called code changes... k-boom.
In that situation, the program terminates buh-bye sayonara. The user's
work is lost, customer service gets lots of calls from irate customers,
developers get to work 80 hours of emergency crunch time to resolve the bug
-- all because of throw(something) specifications that do only harm, and do
no good (since they are not used at compile time).
PLUS, having a throw(something) specification on a function or method
incurs run-time overhead (!). Remember the C++ rule, your not supposed to
pay for something if you don't put it in? The throw(something)
specification is checked at runtime, and is something that you pay for in
performance.
Not that people should be using the C++ exception mechanism for regular
flow control... but some people do.
How does this happen? Say, for instance, development is done in two
different teams that rarely communicate with each other. Someone misses
that a header file changed with a new or altered throw(something)
specification... bug in waiting.
You could program defensively (and maybe that's not a bad idea). But now
you MUST enforce that all routines that have a throw(something)
specification MUST have a try {} catch(...) {} block at the outermost level
of the body. And what are you gaining? You are consuming all exceptions
pell-nell, cannot handle them (presumably), while somewhere up the stack
perhaps there was a routine which could have handled the mystery
exception. To what benefit...?
More code, less readability, less maintainability, more risk, more chances
for things going awry IN THE PRODUCTION CODE. Not good.
--Eljay
