Exception/Error division in D

[Sean Kelly]

On May 31, 2012, at 1:05 PM, Jens Mueller <jens.k.mueller at gmx.de> wrote:

> Walter Bright wrote:
>> On 5/31/2012 12:40 AM, Jens Mueller wrote:
>>> How do I do a graceful shutdown if finally and scope is not guaranteed
>>> to be executed? Assuming onAssertError, etc. is of no use because I need
>>> to perform different shutdowns due to having different cases or if I
>>> defined my own Error, let's say for some device.
>> 
>> There's no way to guarantee a graceful shutdown.
>> 
>> No way.
>> 
>> If you must have such, then the way to do it is to divide your
>> application into separate processes that communicate via
>> interprocess communication, then when one component fails the rest
>> of your app can restart it or do what's necessary, as the rest is
>> not in an invalid state.
> 
> Okay, let's assume I have separate processes maybe even processes on
> different machines. In one process I get an error. Let's say I want to
> trigger the other process that it restarts the process or just logs the
> event whatever makes sense.
> How do I do this if it not guaranteed that finally/scope blocks are
> being executed?
> 
> I don't need a guarantee that the shutdown will work in each and every
> case. All I need is the possibility to perform a more graceful shutdown.

You pretty much need a local process monitor. This is needed anyway, since not every failure may throw. Say SIGBUS on Posix, for example.