Re: Coding style question

On 11/3/06, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> imad <immaad@gmail.com> writes:
> > Well, its about the coding style. And I doubt there exists a data type
> > which may not have
> > an initializer. A NULL / Zero is an option in all cases and you can do
> > whatever you want to assign it a value immediately after the
> > initialization section. My two cents!
>
> Actually, there are a lot of situations where putting an initializer is
> definitely *bad* style in my opinion, because it can hide errors of
> omission that the compiler would otherwise find for you.  The most
> common example you'll see in the Postgres code is variables that should
> be set in each branch of an if or switch construct:
>
>         int     val;
>
>         switch (foo)
>         {
>                 case A:
>                         val = 42;
>                         break;
>                 case B:
>                         val = 52;
>                         break;
>                 ...
>                 default:
>                         elog(ERROR, ...);
>                         val = 0;  /* keep compiler quiet */
>                         break;
>         }
>
>         return val;
>
> Someone might think it better to initialize val to 0 and get rid of the
> useless (unreachable) assignment in the default case, but I say not.
> With this structure, you'll get an uninitialized-variable warning if
> you forget to set "val" in any one of the cases of the switch.  That's
> a check worth having, especially if the code is at all complicated
> within the cases.
>
> When the variable is going to be set anyway in straight-line code at the
> top of the function, then it's mostly a matter of taste whether you set
> it with an initializer or an assignment.  But whenever there are
> multiple places that might need to set it, I try to structure the code
> to exploit the compiler's ability to catch uninitialized variables,
> and that means not using an initializer.
>
>                         regards, tom lane
>

Thats right!
The next thing is that, should this be left out on the compiler? I
mean, there may still be some scenarios where compiler won't be able
to help us. For instance, passing an uninitialized variable to a
function by reference.

Regards
--Imad