Experimental Physics and
Industrial Control System

Benjamin Franksen <[email protected]> · Wed, 13 Jun 2001 23:50:08 +0200

Redman, Russell O. wrote:
> 
> There is a stylistic issue in that the for loop tests for the completion of
> the loop using "flink != 0", instead of "flink != NULL".  Practically, they
> are the same test but since pointers are (or should be) initialised to NULL,
> they should also be tested against NULL.  This stylistic defect occurs in a
> variety of places throughout the program.

Just a little side-remark: I got the impression people will NEVER EVER
agree wether to use 0 or NULL. Matter of style, as you said. [Personally
I like to use 0 (zero) because comparison reduces to logical test i.e.
if(p) instead of if(p != 0) which is redundant. AFAIK, C language
definition garuantees this to work as expected.]

You are right, however, that choice should be consistent, i.e.
initialization same as comparison.

Much more important: Good job done, debugging e2db!

While you're at it, have you ever got error message like following:

----  Loc: motor:slider
Warning: Port property "typ(U0)" should not equal "val".

----  Loc: motor:slider
Warning: Port property "val(U0)" does not exist, treating as field ref.

Always appears if you use a free port, assign it some record field and
connect the port to something.

Problem is when you fix it, it breaks. Meaning *with* error message
produces correct db, but if you chose "path" for port property you get
wrong result. Took me quite a while then, to find out what was wrong:
why, my links simple weren't there after I "fixed" it.

Ben

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System