Re: Exiting from a function or procedure

[dvdeug@x8b4e53cd.dhcp.okstate.edu (David Starner)]

On 22 Apr 2000 12:33:32 -0700, Ray Blaak <blaak@infomatch.com> wrote:
>tmoran@bix.com writes:
>> > So NEVER EVER ignore warnings, consider them as errors.  In
>> > fact you might want to use -gnatwe so the compiler will
>> > treat them as errors enforcing this discipline.
>> 
>> This is not always a good idea.  For instance
>>      if OK then
>>        return some_value;
>>      else
>>        Log_And_Raise_Error;
>>      end if;
>>    end some_function;
>> is a perfectly legitimate paradigm in Ada that would become
>> illegal in Gnat with -gnatwe, since the compiler doesn't know
>> that Log_And_Raise_Error will never return.
>
>I always put in a dummy return in these cases, just to avoid such warnings, and
>for safety if the log routine ever *doesn't* raise an exception (e.g. maybe due
>to some maintenance change in the future).

Of course, that masks a bug. Log_And_Raise_Error is defined to raise an 
exception - if it doesn't then it's buggy. Either that, or the maintenance
programmer should have fixed every use of Log_And_Raise_Error - and a dummy
return is unlikely to be the correct fix. At least in developement, raising
Program_Error is a good result.

-- 
David Starner - dstarner98@aasaa.ofe.org
Finger dvdeug@x8b4e53cd.dhcp.okstate.edu for more information.
Only a nerd would worry about wrong parentheses with
square brackets. But that's what mathematicians are.
   -- Dr. Burchard, math professor at OSU