[Info-vax] VMS Cobol - GnuCOBOL

[Johnny Billquist]

On 2023-02-28 18:53, bill wrote:
> On 2/28/2023 12:04 PM, Denys Beauchemin wrote:
>> On Monday, February 27, 2023 at 7:11:36 PM UTC-6, Robert A. Brooks wrote:
>>> On 2/27/2023 6:35 PM, Arne Vajhøj wrote:
>>>
>>>> But isn't that the case for all VMS compilers? I know
>>>> I use /DEB/NOOP for both Fortran, Pascal and C when I want
>>>> to debug.
>>> Reagan may weigh in here, but I'm pretty sure that DEC suggested using
>>> /DEBUG/NOOP when using the debugger for any language with an 
>>> optimizer back in
>>> the 80's; if so, then that's been a pretty consistent message.
>>>
>>> -- 
>>>
>>> --- Rob
>> Speaking of debuggers.
>>
>> I'm not clear on how you can actually debug a gnucobol program, since 
>> it's C in reality.
> 
> To be honest, there probably isn't really a debugger for GnuCOBOL.
> We really need to put this one misconception to rest.  You are not
> supposed to do anything with the C code generated by the GnuCOBOL
> compiler.  It's an intermediate language not intended for human
> consumption.  Every compiler I have worked with so far takes the
> original source and converts it into some intermediate language.
> Some use RTL.  Some use assembler.  GnuCOBOL uses C.  RATFOR uses
> Fortran.  :-)  We even have the Chung/Yuen Tiny Pascal which converted
> to a P-code that could be further processed into 8080 Assembler and
> then further processed into an executable for the Northstar.
> None of these intended humans to read, understand or manipulate
> the intermediate forms.  So lets just ignore the fact that GnuCOBOL
> converts COBOL into C.  It really converts COBOL into an executable
> program on the host computer just like every other compiler.

All very true. But that does not change the fact that when you point a 
debugger at it, it will trace the binary back to C, not Cobol, unless 
you extend the debugger to do the reversing of the C to the original 
Cobol code. And unless you do some tricks to the C compiler, a debugger 
don't even have a way to know that it wasn't originally C code.

But it is the same kind of problems all those other languages also have, 
and in fact even native compiled languages. After all, the debugger only 
sees the machine code, and hopefully a bunch of symbols and other 
meta-data the compiler left behind.

   Johnny