>Walter, what do you think of CC5X?  Of Clyde's review?
>
>Andy
>
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>             INTRODUCTORY PRICING ENDS JULY 1, 1999
>==================================================================
>Andy Kunz               Life is what we do to prepare for Eternity
>------------------------------------------------------------------
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>==================================================================
>
|

>For automatic variables, no, but static duration variables, yes.
>
>ANS X3.159-1989 3.5.7 Initialization
>        "If an object that has automatic storage duration is not initialized
>explicitly, its value is indeterminate. If an object that has static
>storage duration is not initialized explicitly, it is initialized
>implicitly as if every member that has arithmetic type were assigned 0 and
>every member that has pointer type were assigned a null pointer constant."
>
>It is not unreasonable, IMO, for compilers for small processors to, at
>least optionally, waive the implicit initialization of static duration
>objects, as it's good style to explicitly initialize any variable upon
>whose startup-value the program will depend and initializing a bunch of
>locations to zero when it's not necessary can chew up a lot of cycles at
>startup that could be put to better use.
>
>        Jim
>
>James Grosbach
>Development Systems
>Microchip Technology
>KILLspamjames.grosbachspamBeGonemicrochip.com
>
|

> At 09:45 AM 6/7/99 -0400, you wrote:
> >I find it disheartening that CC5X doesn't zero all variables at
> >initialization, as per the C spec.  CC5X has taken shortcuts when it didn't
> >suit their fancy.  I think Clyde did a great service by giving an honest
> >review of the product.
>
> Andy, I never heard of any part of the C spec that guarantees zeroed
> variables at startup! I have used Borland Turbo C++ for several years for
> programming PCs and I never remember any such guarantee. IN fact, I seem to
> remember just the opposite being said (i.e.,you must initialize the vars
> yourself,as opposed to other higher-level languages such as BASIC).
>
> Sean
>
>

>On Mon, Jun 07, 1999 at 06:10:02PM -0400, Sean Breheny wrote:
>
>> Oh, BTW, another C question for the experts: Is this legal ANSI C?
>
>Yes, functions in C can have inner blocks, which represent a new scope,
>and can have their own local variables.
>
>
>Regards, Clyde
>
>--
>Clyde Smith-Stubbs               |            HI-TECH Software
>Email: TakeThisOuTclyde.....TakeThisOuThtsoft.com          |          Phone            Fax
>WWW:   http://www.htsoft.com/    | USA: (408) 490 2885  (408) 490 2885
>PGP:   finger TakeThisOuTclydeKILLspamspamhtsoft.com   | AUS: +61 7 3355 8333 +61 7 3355 8334
>---------------------------------------------------------------------------
>HI-TECH C: compiling the real world.
>
|

> on me ;-)
>
> Oh, BTW, another C question for the experts: Is this legal ANSI C?
>
> #include <stdio.h>
>
> void main ( void )
> {
>         printf ( "Hello!\n" );
>         {
>                 int j;
>                 printf ( "Hi!\n" );
>         };
> };
>
> I always thought that extra sets of braces (without starting a new

> after the start of code like this (unless beginning a new function) was
> illegal. I thought those things were only allowed in C++. HOWEVER, Turbo
> C++ compiles it fine EVEN with the C++ functionality turned off (should
> make it a regular C compiler).
>
> Can someone please set me straight?
>
> Thanks,
>
> Sean
>
>
> At 01:45 PM 6/7/99 -0400, you wrote:
> >For automatic variables, no, but static duration variables, yes.
> >
> >ANS X3.159-1989 3.5.7 Initialization
> >        "If an object that has automatic storage duration is not

> >
> >It is not unreasonable, IMO, for compilers for small processors to, at
> >least optionally, waive the implicit initialization of static duration
> >objects, as it's good style to explicitly initialize any variable upon
> >whose startup-value the program will depend and initializing a bunch of
> >locations to zero when it's not necessary can chew up a lot of cycles at
> >startup that could be put to better use.
> >
> >        Jim
> >
> >James Grosbach
> >Development Systems
> >Microchip Technology
> >spamBeGonejames.grosbach@spam@spam_OUTmicrochip.com
> >
> |
> | Sean Breheny
> | Amateur Radio Callsign: KA3YXM
> | Electrical Engineering Student
> \--------------=----------------
> Save lives, please look at http://www.all.org
> Personal page: http://www.people.cornell.edu/pages/shb7
>
>
> TakeThisOuTshb7spamcornell.edu ICQ #: 3329174
> ________________________________________________________
> NetZero - We believe in a FREE Internet.  Shouldn't you?
> Get your FREE Internet Access and Email at
> http://www.netzero.net/download/index.html

>Sean,
>
>Sorry, I can't really comment on whether the extra braces are illegal in
>ANSI C.  I can say that I too started with Turbo C and move to Borland C++
>3.xx - 5.xx.  As far I remember, it has always been legal to use braces to
>define a new scope.  Variables declared within the braces are local to that
>scope only.  Always used a mix of C/C++ so maybe that's why I've never
>noticed otherwise.
>
>I compiled the following in a file called test.c under Borland C++ 5.02.
>With i = i + j commented, it compiles without error. Uncommenting the line
>produces an error that j is undefined. Note that compiling a file with the
>.c extension should compile it as C source not C++. I compiled with the
>compiler set to both ANSI language compliance and then Kernighan and
>Ritchie without error.
>
>int test()
>        {
>
>        int i = 5;
>
>        {
>        int j = 1;
>        j = j+1;
>        }
>
>        //i = i + j;
>
>        }
>
>I know that this doesn't explicitely answer your question, but I suspect
>that using braces to create a local scope is legal ANSI C.
>
>Eric
>
>On Monday, June 07, 1999 5:10 PM, Sean Breheny [SMTP:shb7EraseMECORNELL.EDU]
>wrote:
>> Thanks for the info.
>>
>> I didn't know that we were making a distinction between different kinds
>of
>> variables in the earlier discussion, but I can see how it is important.
>> Probably my Turbo C++ isn't completely ANSI compatible because I seem to
>> remember defining global arrays and upon inspecting them,finding only the
>> portion that I actually set being initialized,the rest containing
>"random"
>> data.
>>
>> Actually, I just went and tried it,and lo and behold,it IS initializing
>> global arrays to zero. I stand corrected, must be my memory playing
>tricks
>> on me ;-)
>>
>> Oh, BTW, another C question for the experts: Is this legal ANSI C?
>>
>> #include <stdio.h>
>>
>> void main ( void )
>> {
>>         printf ( "Hello!\n" );
>>         {
>>                 int j;
>>                 printf ( "Hi!\n" );
>>         };
>> };
>>
>> I always thought that extra sets of braces (without starting a new
>function
>> or a for, while, etc.) were illegal in ANSI C AND that declaring
>variables
>> after the start of code like this (unless beginning a new function) was
>> illegal. I thought those things were only allowed in C++. HOWEVER, Turbo
>> C++ compiles it fine EVEN with the C++ functionality turned off (should
>> make it a regular C compiler).
>>
>> Can someone please set me straight?
>>
>> Thanks,
>>
>> Sean
>>
>>
>> At 01:45 PM 6/7/99 -0400, you wrote:
>> >For automatic variables, no, but static duration variables, yes.
>> >
>> >ANS X3.159-1989 3.5.7 Initialization
>> >        "If an object that has automatic storage duration is not
>initialized
>> >explicitly, its value is indeterminate. If an object that has static
>> >storage duration is not initialized explicitly, it is initialized
>> >implicitly as if every member that has arithmetic type were assigned 0
>and
>> >every member that has pointer type were assigned a null pointer
>constant."
>> >
>> >It is not unreasonable, IMO, for compilers for small processors to, at
>> >least optionally, waive the implicit initialization of static duration
>> >objects, as it's good style to explicitly initialize any variable upon
>> >whose startup-value the program will depend and initializing a bunch of
>> >locations to zero when it's not necessary can chew up a lot of cycles at
>> >startup that could be put to better use.
>> >
>> >        Jim
>> >
>> >James Grosbach
>> >Development Systems
>> >Microchip Technology
>> >RemoveMEjames.grosbachEraseMEspam_OUTmicrochip.com
>> >
>> |
>> | Sean Breheny
>> | Amateur Radio Callsign: KA3YXM
>> | Electrical Engineering Student
>> \--------------=----------------
>> Save lives, please look at http://www.all.org
>> Personal page: http://www.people.cornell.edu/pages/shb7
>>
>>
>> @spam@shb7RemoveMEEraseMEcornell.edu ICQ #: 3329174
>> ________________________________________________________
>> NetZero - We believe in a FREE Internet.  Shouldn't you?
>> Get your FREE Internet Access and Email at
>> http://www.netzero.net/download/index.html
>
|