Re: [epics-modules/asyn] Throw exception if we can't register interfaces (#43)

[Andrew Johnson <anj@aps.anl.gov>]

Hi Eric,

On 02/08/2017 12:15 PM, Eric Norum wrote:
> Maybe it’s time for the IOC shell to actually look at the return values
> from the functions it calls.  In conjunction with some sort of
> equivalent to the UNIX shell ‘-e’ flag it could prevent st.cmd scripts
> from proceeding in the face of error returns from configuration functions.

I would be in favour of that, although currently iocsh.h declares:

> typedef void (*iocshCallFunc)(const iocshArgBuf *argBuf);
> 
> epicsShareFunc void epicsShareAPI iocshRegister(
>     const iocshFuncDef *piocshFuncDef, iocshCallFunc func);

We would have to duplicate both of the above to add a return status; not
hard to do, but the registered commands in all the external support
modules would have to be changed to use that new feature.

Since iocsh is C++ code it could also catch exceptions...

If we're going to modify the iocsh interface there are some additional
changes and simplifications I'd like to make, including being able to
register commands through DBD-file entries instead of having to create a
number of data structures and call iocshRegister() for each one from a
registrar function.

- Andrew

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