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Entry  31 Oct 2003, Konstantin Olchanski, , more odb "run number" error checking 
    Reply  01 Nov 2003, Stefan Ritt, , more odb  
       Reply  01 Nov 2003, Konstantin Olchanski, , more odb  
          Reply  14 Nov 2003, Stefan Ritt, , more odb  
Message ID: 107     Entry time: 31 Oct 2003     Reply to this: 108
Author: Konstantin Olchanski 
Subject: more odb "run number" error checking 
I added error checking to the places where we read "/runinfo/run number". In
general, I do this:

  status = db_get_value("/runinfo/run number",&run_number);
  assert(run_number >= 0); (and run_number>0, where appropriate)

Here is the rationale: if we cannot read the run number, something must be
very terribly wrong. I cannot think of any recovery action other than
abort() and make a core dump for our debugging enjoyment.

I considered and rejected adding a "retry" loop: if we allow db_get_value()
to intermittently fail, then it's every use has to be wrapped in a retry
loop, which then should be inside db_get_value(), making it pointless to
have external "retry" loops.

I am now pondering on proposing a "db_get_value_cannot_possibly_fail()"
function (it would abort(), exit() with an error or commit harakiri if it
can't get the value). They way most db_xxx() functions are used in midas,
maybe they should be made "void" and "unfailible", with "STATUS
db_xxx_yes_I_can_fail_and_return_an_error_code()" evil twins. I guess this
is why "they" invented C/C++ exceptions. Anyway, something to think about.

Affected files:

ELOG V3.1.4-2e1708b5