[m-users.] Uncaught mercury exception using try []

Zoltan Somogyi zoltan.somogyi at runbox.com
Sat May 29 05:11:11 AEST 2021


2021-05-28 07:10 GMT+10:00 "Sean Charles (emacstheviking)" <objitsu at gmail.com>:
> Hmmm. They -work- in so far as they generate output when I set the relevant environment variables so I am not sure I understand why they are -useless- to that extent.

Logging, such as your calls to atrace, can tell you two things.

1 When you get output, it tells you "execution got here, with these values".

2 When you don't get output, it tells you "execution did not get here".

But if the call can be optimized away by the compiler, you cannot tell *anything*
from the absence of logging output. So you are right, those calls are not
fully useless, they are only *half* useless :-(

> so I should be doing, at the relevant call sites,
> 
> 	trace[io(!Dbg) (atrace…) 
> 
> instead of
> 
> 	atrace() :- … blah
> 
> yes? 

Yes.

> Would that mean then I have to repeatedly use runtime(env(“…”)) at every call site as well.

Yes.

Zoltan.


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