[news.eclipse.dsdp.rtsc] Re: Re-throwing an error

[Bob Frankel <bob@xxxxxxxxxxx>]

from what i can tell, calling Error_init (again!) will effectively reset 
the error block....  [i seem to recall an Error_clear function from the 
past, though its implementation was probably just a called to Error_init 
and was therefore dropped]

as an alternative, however, the function below (which is passed 'eb') 
could declare its *own* Error_Block on the stack; the latter Error_Block 
would be passed to Memory_alloc and -- depending upon the outcome -- the 
original 'eb' would be passed to Error_raise....

this approach would be *necessary* if this particular routine want to do 
some cleanup *before* calling Error_raise on the original 'eb'.... why? 
because 'eb' could be NULL and passing it to Memory_alloc could lead to 
premature program termination....

this design also enforces the "one error per one error block" approach...

but still, you can reuse error blocks by simply calling Error_init (again!)


Ramsey Harris wrote:
> Champs,
>
> Is it safe to call Error_raise() on a signaled error block? Or might 
> some state information from the previous error "leak" into the second 
> error and invalidate its state?
>
> For example, I have some code which requests memory. If the heap runs 
> out of memory, it will raise an error. But this is a low level and very 
> common operation. I would like to add a second error event to the error 
> log which indicates who was requesting the memory.
>
> packet = (RcmClient_Packet*)Memory_alloc(NULL, size, sizeof(Ptr), eb);
>
> if (Error_check(eb)) {
>    Error_raise(eb, RcmClient_E_packetAllocFailed, size, 0);
>    goto leave;
> }
>
> Is this safe to do, or must I call Error_init() before raising the 
> second error?
>
> Thanks
> ~ Ramsey