Re: crash when invoking service

[Richard Frith-Macdonald]

On Thursday, May 3, 2001, at 11:06 PM, Frederic wrote:

> Hello,
>
> When trying to debug the "Service" issue in GSDict, I found a problem in
> the function BOOL NSPerformService(NSString *serviceItem, NSPasteboard
> *pboard):
>
> In the original code, the "connection" local variable is not initialized
> to nil. When the line "connection = [(NSDistantObject*)provider
> connectionForProxy];" is executed (arround line 1276), for some reason,
> "provider" doesn"t respond to connectionForProxy:. An exception is
> raised and, I guess, connection is not set. Then is crashes two line
> after at "[connection setRequestTimeout: seconds];". I changed the code
> to set connection to nil before the call but when the exception is
> raised, connection is set to an invalid value that still leads to the
> crash.
>
> So my question is: when an exception is raised in a method, what should
> the return value of the method be equal to? (especially when it is a
> pointer)

1. I've rewritten this code to cope with the case where an app is 
providing
a service to itsself ... please try the new version.

2. The exception was raised because, for an app providing the service to 
itsself,
the 'provider' is a local object rather than a proxy to a remote object.

3. I don't know how you could get a problem a few lines later ... the 
exception
should cause control to return to the enclosing exception handler.

In answer to your question ... when an exception is raised in a method, 
there
should be *NO* return value from the method because the method does not 
return.
If a method creates an exception handler and calls something that raises 
an exception
inside that handler, then the handler should catch the exception and the 
method should
then continue to return a value the normal way.