[En-Nut-Discussion] Feature Request 1572837: mutex API nesting level info

[duane ellis]

I've not been following this entire conversation about recursive mutexes 
in detail.

 >> [about recursive mutexes]

 >> That's exactly the point: they are bad because they encourage you to 
do  the wrong stuff

There is nothing wrong with recursive mutexes. 

There is an old saying: 
        If your only tool is a hammer, everything is a nail.

I have smashed my fingers with that proverbial hammer a few times.  
Sometimes - it was the only type of nail I had to build my project. 
Sometimes - I did  not know any better - and I learned. Smashing fingers 
hurt. At times I decided to *never* use that type of nail again. Over 
time - I learned how to use that type of nail properly and changed my 
mind. In your home, I bet there are over 20 different types and sizes of 
nails. The skilled builder who built your home knew when and where to 
use each type of nail. (let us hope he was a skilled builder!)

Mutexes are like nails they are building tools, a skilled 
craftsmen(person) knows how to choose right one.

The tool box (ethernut) is missing a few other types of nails that 
others need.

-------

About the "David Butenhof" - article that somebody linked to:

    http://www.zaval.org/resources/library/butenhof1.html

his basic thesis is this:

     Recursive locks are so easy - to get wrong - that you should never 
use them.
     People are lazy - and do not properly study the situation at hand 
and choose badly.

Put another way:
  
    It is easy to smash your finger with that type of nail.
    So - NEVER use that type of nail.
    Period. Full Stop.  End of Story.
    There should be laws against that type of nail.

You know what?

    A scalpel (surgeons knife) has the same property. Either it is in 
the hands of an idiot, or a skilled surgeon.

As David Butenhof says:
  
    Recursive mutexes are a hack. There's nothing wrong
    with using them, but they're a crutch. Got a broken leg
    or library? Fine, use the crutch. But at least be aware
    that you're using a crutch, and why;

yes, he goes on, I cut him off - he mentions a a doctor.. To paraphrase 
him a bit -

    Maybe - given the situation at hand...
        recursive mutexes are exactly what the skilled surgeon ordered.

I like to think most of us are of the "skilled surgeon" type.

-Duane.