Re: reporting typedef errors automatically

[Roman Mashak]

Hello, Jack!
You wrote on Thu, 29 May 2008 20:38:35 -0500:

JKThis is a pretty stupid idea, and extremely non-portable. Who's
JKnot-so-bright idea is it?

http://www.oreillynet.com/pub/a/network/2003/10/07/michael_barr.html

[skip]
What portable way would you suggest? Checking the CHAR_BITS?

With best regards, Roman Mashak. E-mail: mrv@tusur.ru

[Chris Thomasson]

Re: reporting typedef errors automatically


"Roman Mashak" <mrv@tusur.ruwr ote in message
news:g1nsl5$6no $1@relay.tomsk. ru...

Hello, Jack!
You wrote on Thu, 29 May 2008 20:38:35 -0500:
>
JKThis is a pretty stupid idea, and extremely non-portable. Who's
JKnot-so-bright idea is it?

http://www.oreillynet.com/pub/a/network/2003/10/07/michael_barr.html

>
[skip]
What portable way would you suggest? Checking the CHAR_BITS?

[...]

Try something like:



#include <limits.h>

typedef char atomic_word8;
typedef short atomic_word16;
typedef int atomic_word32;

typedef char atomic_word_siz eof_static_asse rt[
sizeof(atomic_w ord8) == 8 / CHAR_BIT &&
sizeof(atomic_w ord16) == 16 / CHAR_BIT &&
sizeof(atomic_w ord32) == 32 / CHAR_BIT
? 1 : -1
];

[Jack Klein]

Re: reporting typedef errors automatically

On Fri, 30 May 2008 12:34:30 -0700, "Roman Mashak" <mrv@tusur.ru >
wrote in comp.lang.c:

Hello, Jack!
You wrote on Thu, 29 May 2008 20:38:35 -0500:
>
JKThis is a pretty stupid idea, and extremely non-portable. Who's
JKnot-so-bright idea is it?

http://www.oreillynet.com/pub/a/network/2003/10/07/michael_barr.html

>
[skip]
What portable way would you suggest? Checking the CHAR_BITS?

The header <stdint.hprovid es minimum and maximum macros for the
exact width integer types, if and only if those particular types are
defined.

As someone else already pointed out, if int8_t and uint8_t exist, the
wider types, if they exist as they almost certainly will, will have
the sizes you check for.

Still, it's much easier to do something like this:

#include <stdint.h>

#ifndef INT8_MAX

....do something about it

#endif

But if the types you need are there, why do you care what their sizes
are in bytes? Are you actually expecting a compiler to come with
errors in its <stdint.hheader ?

In the Barr article you quote, he is talking about a way of testing a
home brew <stdint.hfor a compiler that doesn't come with one.
Frankly, anybody who can't get this right on the first try probably
shouldn't be trying.

--
Jack Klein
Home: http://JK-Technology.Com
FAQs for
comp.lang.c http://c-faq.com/
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alt.comp.lang.l earn.c-c++

http://www.club.cc.cmu.edu/~ajo/docs/FAQ-acllc.html

[Roman Mashak]

Re: reporting typedef errors automatically

Hello, Jack!
You wrote on Fri, 30 May 2008 21:41:48 -0500:

??>Hello, Jack!
??>You wrote on Thu, 29 May 2008 20:38:35 -0500:
??>>
JK>>This is a pretty stupid idea, and extremely non-portable. Who's
JK>>not-so-bright idea is it?
??>http://www.oreillynet.com/pub/a/netw...hael_barr.html
??>>
??>[skip]
??>What portable way would you suggest? Checking the CHAR_BITS?

JKThe header <stdint.hprovid es minimum and maximum macros for the
JKexact width integer types, if and only if those particular types are
JKdefined.
[skip]
I got this yet, thanks though.


With best regards, Roman Mashak. E-mail: mrv@tusur.ru