Re: signed is undefined and has been since 1992 (in GCC)

[Gabriel Dos Reis <gdr@integrable-solutions.net>]

Robert Dewar <dewar@adacore.com> writes:

| Gabriel Dos Reis wrote:
| > Robert Dewar <dewar@adacore.com> writes:
| > | Olivier Galibert wrote:
| > | | > Calling a large part of the programs out there, including a non
| > | > negligible subpart of what I personally write either "blatantly buggy"
| > | > or "subtly-incorrect" is somewhat childish and insulting.
| > | | nope, I don't see it that way at all, this is just a statement
| > of fact
| > | wrt the ISO standard. You may want C or C++ to be different from what
| > | it is, but the standard is widely accepted,
| > Those standards are widely accepted and so are very facts that they
| > do
| > have connections with hardware.  In fact, the respective committees
| > do work seriously on producing TRs for embedded systems and access to
| > hardware semantics.
| 
| I think you miss my point completely about hardware semantics. Let me
| try, though I am dubious it will be clear.

Maybe because it is an already confused statement?

|  The type int in C is not
| a hardware type, it is a type with properties defined by the standard.
| There is not necessarily any unique expectation on how this will be
| mapped to hardware, or what operations will be mapped. The only
| requirement is that the required semantics of int in the standard
| are preserved. For instance on the IBM mainframe one might use signed
| or unsigned operations to implement int operations. On the original
| MIPS one might use trapping or non-trapping arithmetic (either would
| be valid).

nice exercise in language lawyering but, I think your forgot the
qualification in the claim: if the hardware I'm targetting provides the
specific semantics I want.  Your scenario does not disqualify it.

| Yes, sometimes you need access to the hardware and need to control
| exactly what is generated, but using int is not a mechanism that
| provides any such guarantee.

except that those whose produced the document had an intended
semantics and the expectations are connected with some reality which
you would deny.

       [#5]  An  object  declared  as type signed char occupies the
       same amount of  storage  as  a  ``plain''  char  object.   A
       ``plain''  int  object has the natural size suggested by the
       architecture of the execution environment (large  enough  to
       contain any value in the range INT_MIN to INT_MAX as defined
       in the header <limits.h>).

C and C++ are general programming language geared toward system
programming. 

-- Gaby