A byte can be greater than 8 bits?

[borophyll]

As I read it, C99 states that a byte is an:

"addressabl e unit of data storage large enough to hold any member of
the basic character
set of the execution environment" (3.6)

and that a byte must be at least 8 bits:

"The values given below shall be replaced by constant expressions
suitable for use in #if
preprocessing directives. Moreover, except for CHAR_BIT and
MB_LEN_MAX, the
following shall be replaced by expressions that have the same type as
would an
expression that is an object of the corresponding type converted
according to the integer
promotions. Their implementation-defined values shall be equal or
greater in magnitude
(absolute value) to those shown, with the same sign."

number of bits for smallest object that is not a bit-field (byte)
CHAR_BIT 8 (5.2.4.2.1)

Does this mean that a byte can be larger than 8 bits (ie CHAR_BIT >
8)? I have gotten the impression that a byte, or unsigned char, was
always 8 bits, but perhaps I was wrong. If I am not, is there
somewhere in the standard that defines a byte as always being 8 bits?

Regards,
B.

[jacob navia]

Charlie Gordon wrote:

"Mike Smith" <mi*********@no .spam.btconnect .coma écrit dans le message de
news: Lt************* *************** **@bt.com...

>The hardware is Bull DPS9000 (a descendant of the Honeywell L66
range that was itself a descendant of the GE-600). The GCOS8 operating
system is still in active use today.

The current generation of Bull DSP9000 (NovaScale 9xxx) machines run Gcos8
in emulation mode on Intel Itanium 2 processors. Not exactly the old 36 bit
architecture anymore.

GCOS8 under emulation in an Itanium!

This can ONLY be possible at Bull. Of course they HAD to choose
the Itanic, they have chosen ALL weird architectures born dead
since 1982... or more!

If something is bad conceived, eventually Bull will buy it, that
is obvious. The Itanic is a total failure, and Bull will chose
it.

--
jacob navia
jacob at jacob point remcomp point fr
logiciels/informatique
http://www.cs.virginia.edu/~lcc-win32

[Martin Wells]

jacob:

Given you don't care about porting from one version of windows to the
next, it's hardly suprising you don't care about this.

Martin

????
lcc-win runs under
o windows 2000
o windows 98
o windows XP (32 and 64 bits)
o windows server 32 and 64 bits
o windows Vista (32 and 64 bits)

It even runs under windows ME!

Linux versions are available. You just speak without any
knowledge of what I am doing.

I'm speaking of your experience with using int instead of size_t, and
the headache it caused you when you got truncation warning when you
ported to another windows version.

When I myself am writing code, I put in casts wherever I'm going to
get an obvious truncation warning. For instance:

#define MONTHS_IN_YEAR 12

char unsigned start_month = 4; /* A value in the range 0 through
11, 0 = Jan, 11 = Dec */

unsigned months_passed = 183; /* A value in the range 0 through
1800 */

char unsigned current_month = (char unsigned)(start _month +
months_passed % MONTHS_IN_YEAR)
/* Cast to suppress truncation warning */

Given the choice of
a) Using size_t
and
b) Using casts

, you chose neither, and ended up with 5 billion warning when you
compiled your code. Granted, the code may still have been portable,
but I'm sure you could have done without those redundant warnings.

Martin

[Charlie Gordon]

"Martin Wells" <wa****@eircom. neta écrit dans le message de news:
11************* ********@k79g20 00...legro ups.com...

jacob:

Given you don't care about porting from one version of windows to the
next, it's hardly suprising you don't care about this.

Martin

????
lcc-win runs under
o windows 2000
o windows 98
o windows XP (32 and 64 bits)
o windows server 32 and 64 bits
o windows Vista (32 and 64 bits)

It even runs under windows ME!

Linux versions are available. You just speak without any
knowledge of what I am doing.

I'm speaking of your experience with using int instead of size_t, and
the headache it caused you when you got truncation warning when you
ported to another windows version.

When I myself am writing code, I put in casts wherever I'm going to
get an obvious truncation warning. For instance:

#define MONTHS_IN_YEAR 12

char unsigned start_month = 4; /* A value in the range 0 through
11, 0 = Jan, 11 = Dec */

unsigned months_passed = 183; /* A value in the range 0 through
1800 */

char unsigned current_month = (char unsigned)(start _month +
months_passed % MONTHS_IN_YEAR)
/* Cast to suppress truncation warning */

The need for these casts is a real pain. I'm glad gcc does not produce them
unless you specifically require them. In this particular case, I think your
computation is wrong, the line should read:

unsigned char current_month = (start_month + months_passed) %
MONTHS_IN_YEAR;

Written this way, it would not take a smart compiler to figure the result
should be in the range 0..11 and therefore always fits in an unsigned char.

Given the choice of
a) Using size_t
and
b) Using casts

, you chose neither, and ended up with 5 billion warning when you
compiled your code. Granted, the code may still have been portable,
but I'm sure you could have done without those redundant warnings.

Given the non-sensical choice made for win64 to have
sizeof(long)==s izeof(int)==4 and sizeof(size_t)= =sizeof(long long)==8,
mixing int and size_t irresponsibly is not a wise choice.

Furthermore, I think there should be provision in the compiler to enable or
disable each individual warning, either with a command line switch, a
configuration file option or possibly a #pragma.

--
Chqrlie.

[CBFalconer]

jacob navia wrote:

Martin Wells wrote:

>jacob:

>>Of course, there are maybe 10-20 installations all over the
world, but... I would not care really.

Given you don't care about porting from one version of windows to
the next, it's hardly suprising you don't care about this.

????
lcc-win runs under
o windows 2000
o windows 98
o windows XP (32 and 64 bits)
o windows server 32 and 64 bits
o windows Vista (32 and 64 bits)

It even runs under windows ME!

No it doesn't. I can't speak for other combinations, but W98 runs
on a '486. lcc-win32 does not.

--
Chuck F (cbfalconer at maineline dot net)
Available for consulting/temporary embedded and systems.
<http://cbfalconer.home .att.net>

--
Posted via a free Usenet account from http://www.teranews.com

[Kenneth Brody]

Keith Thompson wrote:

>
Kenneth Brody <ke******@spamc op.netwrites:

Keith Thompson wrote:

[...]

A small quibble: Putting C identifiers or keywords in all-caps for
emphasis is not a good idea. void is a keyword; VOID is an identifier
and could very plausibly be a macro name (for example, I've seen code
that conditionally uses ``#define VOID int'' for pre-ANSI
compatibility).

BTDTGTHF.

?

It's my update to "BTDTGTTS":

Been There, Done That, Got The Header Files.

--
+-------------------------+--------------------+-----------------------+
| Kenneth J. Brody | www.hvcomputer.com | #include |
| kenbrody/at\spamcop.net | www.fptech.com | <std_disclaimer .h|
+-------------------------+--------------------+-----------------------+
Don't e-mail me at: <mailto:Th***** ********@gmail. com>

[jacob navia]

CBFalconer wrote:

jacob navia wrote:

>Martin Wells wrote:

>>jacob:

Of course, there are maybe 10-20 installations all over the
world, but... I would not care really.
Given you don't care about porting from one version of windows to
the next, it's hardly suprising you don't care about this.

????
lcc-win runs under
o windows 2000
o windows 98
o windows XP (32 and 64 bits)
o windows server 32 and 64 bits
o windows Vista (32 and 64 bits)

It even runs under windows ME!

No it doesn't. I can't speak for other combinations, but W98 runs
on a '486. lcc-win32 does not.

lcc-win32 should run in windows 98 unless you use a 486

--
jacob navia
jacob at jacob point remcomp point fr
logiciels/informatique
http://www.cs.virginia.edu/~lcc-win32

[Martin Wells]

Chqrlie:

In this particular case, I think your
computation is wrong, the line should read:

unsigned char current_month = (start_month + months_passed) %
MONTHS_IN_YEAR;

Well let's say that the starting month is April (i.e. 3), and that 14
months have passed. Therefore, the new month should be May (i.e. 5)

Taking *my* formula, we have:

start_month + months_passed % MONTHS_IN_YEAR
3 + 14 % 12
3 + 2
5

Taking *your* formula, we have:

(start_month + months_passed) % MONTHS_IN_YEAR
(3 + 14) % 12
17 % 2
5

Both work.

Written this way, it would not take a smart compiler to figure the result
should be in the range 0..11 and therefore always fits in an unsigned char.

....but the question is what proportion of compilers do it? For now I
think I'll stick to the casts.
Martin

[Charlie Gordon]

"CBFalconer " <cb********@yah oo.coma écrit dans le message de news:
47************* **@yahoo.com...

jacob navia wrote:

>Martin Wells wrote:

>>jacob:

Of course, there are maybe 10-20 installations all over the
world, but... I would not care really.

Given you don't care about porting from one version of windows to
the next, it's hardly suprising you don't care about this.

????
lcc-win runs under
o windows 2000
o windows 98
o windows XP (32 and 64 bits)
o windows server 32 and 64 bits
o windows Vista (32 and 64 bits)

It even runs under windows ME!

No it doesn't. I can't speak for other combinations, but W98 runs
on a '486. lcc-win32 does not.

Come on, W98 does not run on a '486, it merely crawls there like a lame dog.

--
Chqrlie.

[Jean-Marc Bourguet]

Martin Wells <wa****@eircom. netwrites:

Chqrlie:

In this particular case, I think your
computation is wrong, the line should read:

unsigned char current_month = (start_month + months_passed) %
MONTHS_IN_YEAR;

Well let's say that the starting month is April (i.e. 3), and that 14
months have passed. Therefore, the new month should be May (i.e. 5)

Let's take another example: the starting month is December ie 11 and 11
months have passed. Therefore the new month should be November (10).

Taking *my* formula, we have:

start_month + months_passed % MONTHS_IN_YEAR

11 + 11 % 12 = 11 + 11 = 22. Oops

Taking *your* formula, we have:

(start_month + months_passed) % MONTHS_IN_YEAR

(11 + 11) % 12 = 22 % 12 = 10

Both work.

Not on all inputs.

Yours,
--
Jean-Marc

[Martin Wells]

Jean-Marc:

Taking *my* formula, we have:

start_month + months_passed % MONTHS_IN_YEAR

11 + 11 % 12 = 11 + 11 = 22. Oops

Now that's what I call a logic bug. :O

Martin