access(FULLPATH, xxx);

Robert Bonomi bonomi at
Sat Jan 14 09:51:02 UTC 2012

> From owner-freebsd-questions at  Sat Jan 14 02:32:15 2012
> Date: Sat, 14 Jan 2012 09:28:21 +0100
> From: Polytropon <freebsd at>
> To: Robert Bonomi <bonomi at>
> Cc: freebsd-questions at
> Subject: Re: access(FULLPATH, xxx);
> On Sat, 14 Jan 2012 02:00:12 -0600 (CST), Robert Bonomi wrote:
> > To repeat some advice from one of my Computer Science professors, many years
> > ago, whenever I asked 'how does it work' questions: "Try it and find out."
> I bet my professor can beat up your professor. :-)
> Mine used to say several times: "Trial and error is NOT
> a programming concept!"

As far as writing applications goes, that is _somewhat_ correct.  

However, 'trial and error' is _not_ the same thing as 'try it and find out'.
See the entire subject area of 'benchmarking'.

And,  the only way to definitively establish if an alternate approach is
'better' -- i.e. 'faster', or 'smaller', or 'more efficient', etc. -- *IS*
to run a trial.

Your professor undoubtedly would not of approved when I wrote bubble-sort
code that _out-performed_ any other sorting technique -- up to the limits
of memory.  Or when I re-wrote an application that used binary searches
of records, with a new version that used a brute-force linear search.  I
thought I could 'do it better/faster' than the existing code, but the only
way to "definitively" find out was to 'try it'.  And the 'trial' proved
out -- the replacement code was 'merely' somewhat over 100 times faster.

As far as 'doing it once' for the purpose of answering a 'how does it work'
question -- where one has _not_ read the documentation, *OR* the existing 
documentation is _not_clear_, then simple experimentation -- to get *the* 
authoritative answer -- is entirly justified.

When I got the 'try it and find out' advice, I was asking questions about
situations where the language _specification_ was unclear -- there were
two 'reasonable interpretations' of what the language inthe speciication
said, and I just wanted to  know which one was the proper interpretation.

Now, given that the language in the specification _was_ abiguous and both 
interpretations were reasonsble, different compiler builders could have 
implemented differently, and 'try it and find out' was _necessary_ to 
establish what that particular implementation did.  <grin>

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