Re: Concatenation and Characters

[cjsonnack@mmm.com (Programmer Dude)]

Jim Rogers wrote:

>> So, bottom line from the answers I've read is that Ada (the language)
>> allows uninitialized variables to be used which *may* (must?) require
>> a run-time exception.... but what if the random value in the variable
>> isn't a contraint violation?  Does that mean an uninitialized variable
>> *could* be taken seriously and never detected as having a random bit
>> pattern?
> 
> If the compiler detects that you are attempting to use an uninitialized
> value it will issue a diagnostic message. It is never a good thing to
> release a program without first addressing and eliminating all compiler
> diagnostic messages.

Oh, I agree completely.  I have--where possible--my compilers set to
treat warnings as errors when compiling for release.

But is this *required* behavior or QOI behavior?  Some of the posts
seem to suggest this is not required by the language spec, and THAT'S
what I'm finding slightly surprising.

I guess I'm wondering what behavior the language requires.  If it is
required that uninitialized variables never be evaluated, I can see
an implementation choosing not to attempt to diagnose this at compile
time and using another mechanism to detect it at run-time (such as
special values or descriptor bits or whatever).

Upthread Preben Randhol wrote this:

| with Ada.Text_IO; use Ada.Text_IO;
| 
| procedure uninit is
|    A  : Integer;
|    B  : Integer := 2;
| begin
| 
|    if A > B then
|       Put_Line ("A is greater than B");
|    else
|       Put_Line ("B is greater than A");
|    end if;
| end uninit;

Maybe my question is best stated thus: is there any correct implentation
of Ada that would allow this code to run?

-- 
|_ CJSonnack <Chris@Sonnack.com> _____________| How's my programming? |
|_ http://www.Sonnack.com/ ___________________| Call: 1-800-DEV-NULL  |
|_____________________________________________|_______________________|



Opinions expressed herein are my own and may not represent those of my employer.