for(;;) or while(1)?

[Rick]

Hi,

For portability, can an issue arise if we use while(1) for an infinite
loop in C? If so, should we then use for(;;)? Thanks,

Rick

[Thomas Matthews]

Noah Roberts wrote:

Rick wrote:

Hi,

For portability, can an issue arise if we use while(1) for an infinite
loop in C? If so, should we then use for(;;)? Thanks,

Rick

Well using it directly in code it has no matter, but what about this:

#define forever for(;;)

do
{
...x...
} forever;

NR

I didn't think this was valid syntax (after macro substitution):
do
{
/* ...x... */
} for (;;); /* after preprocessor substitution */

My understanding is the syntax is:
do
{
} while();

I don't believe you can replace the "while" with "for" in this
syntax. I've never heard of a "do-for" loop.

--
Thomas Matthews

C++ newsgroup welcome message:
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Other sites:
http://www.josuttis.com -- C++ STL Library book

[Mike Wahler]

"Rick" <rrquick@nosp am-com> wrote in message
news:3f******** @clarion.carno. net.au...

Hi,

For portability, can an issue arise if we use while(1) for an infinite
loop in C? If so, should we then use for(;;)? Thanks,

for(;;) has seven characters, and
while(1) has eight, so the former should
weight slightly less, thus be a bit more
portable.

Also, if carrying the construct in a backback,
the rounded edges of 'f' 'o' and 'r' should
be more comfortable than those pointy 'w', 'h',
'i', and 'l' characters. :-)

Seriously, either one is equally portable. Use
whichever you find most natural, unless you have
coding standards to follow.

-Mike

[Jeremy Yallop]

Rick wrote:

Jeremy Yallop writes:

[snip]

I didn't write any of the quoted text. Please be more careful with
your attributions.

Jeremy.

[Joe Wright]

pete wrote:

Rick wrote:

Hi,

For portability, can an issue arise if we use while(1)
for an infinite loop in C?

My compiler generates a warning for that kind of code,
when I have the warning level high, where I like it.

If so, should we then use for(;;)?

My compiler doesn't generate a warning for that code,
so that's what I use.

--
pete

It's just your compiler's rant about programming style. The while (1)
and for (;;) constructs are identical.
--
Joe Wright mailto:jo****** **@earthlink.ne t
"Everything should be made as simple as possible, but not simpler."
--- Albert Einstein ---

[Minti]

Rick <rrquick@nosp am-com> wrote in message news:<3f******* *@clarion.carno .net.au>...

Hi,

For portability, can an issue arise if we use while(1) for an infinite
loop in C? If so, should we then use for(;;)? Thanks,

Rick

Well I use

while ( 1 )

if I wish to.

BUT

I use

for ( ; ; )

If I wish to.

In terms of performance any *intelligent* compiler would produce the
same binary code. Though a compiler made possibly as a *experimental
project* **might** not do the optimization and might include a sort of
condition for checking the truth value of the expression in while,
which would be true, always. OTOH if you love goto you might also
wanna use

inf_loop:
......
goto inf_loop;

The last one would have the same performence level as that of a for( ;
; ).

why not use

for ( ; 1 ; )

which is *completly* semantically equivalent to the while ( 1 )

--
Imanpreet Singh Arora
imanpreet_arora AT yahoo DOT co DOT in

Aut inveniam viam aut faciam

[Rick]

Sorry about that Jeremy, I meant to qoute Osmium.
Rick

Jeremy Yallop wrote:

Rick wrote:

Jeremy Yallop writes:

[snip]

I didn't write any of the quoted text. Please be more careful with
your attributions.

Jeremy.

[osmium]

Rick writes:

Sorry about that Jeremy, I meant to qoute Osmium.
Rick

Jeremy Yallop wrote:

Rick wrote:

Jeremy Yallop writes:

[snip]

I didn't write any of the quoted text. Please be more careful with
your attributions.

I didn't write it either. Try again.
--
Osmium

[Richard Heathfield]

Thomas Matthews wrote:

Noah Roberts wrote:

Rick wrote:

Hi,

For portability, can an issue arise if we use while(1) for an infinite
loop in C? If so, should we then use for(;;)? Thanks,

Rick

Well using it directly in code it has no matter, but what about this:

#define forever for(;;)

do
{
...x...
} forever;

NR

I didn't think this was valid syntax (after macro substitution):

That was, I believe, the point he was making (i.e. that for(;;) and while(1)
are not interchangeable in all cases).

For what it's worth, I think while(condition ) is clearer than either for(;;)
or while(1).

--
Richard Heathfield : bi****@eton.pow ernet.co.uk
"Usenet is a strange place." - Dennis M Ritchie, 29 July 1999.
C FAQ: http://www.eskimo.com/~scs/C-faq/top.html
K&R answers, C books, etc: http://users.powernet.co.uk/eton

[Arthur J. O'Dwyer]

On Tue, 30 Sep 2003, Ridimz wrote:

"osmium" <r1********@com cast.net> wrote in message

I didn't write it either. Try again.
--
Osmium

Yea you did! Read your reply again! It's attached just in case
you need to see which one!

Maybe osmium means that someone else has been posting to Usenet
using his account... ;-)

Please don't post attachments to non-binaries groups.
A simple link to Google Groups, or, even better, a quick
reminder to "look three messages up the darn thread and
*read* it" would have sufficed.

And in general, don't use spaces in filenames. Some
uudecode clients might not even parse your attachment
correctly (I dunno what any RFC on the topic says; I'm
just pointing out the possibility).

-Arthur

[Minti]

Thomas Matthews <Th************ **********@sbcg lobal.net> wrote in message news:<AO******* **********@news svr17.news.prod igy.com>...

Noah Roberts wrote:

Rick wrote:

Hi,

For portability, can an issue arise if we use while(1) for an infinite
loop in C? If so, should we then use for(;;)? Thanks,

Rick

Well using it directly in code it has no matter, but what about this:

#define forever for(;;)

do
{
...x...
} forever;

NR

I didn't think this was valid syntax (after macro substitution):
do
{
/* ...x... */
} for (;;); /* after preprocessor substitution */

My understanding is the syntax is:
do
{
} while();

Nitpick: replace while() with while(expr)
I don't believe you can replace the "while" with "for" in this
syntax. I've never heard of a "do-for" loop.

Me neither. A lot of books would need to be appended if it existed.
--
Imanpreet Singh Arora
iimmaannpprreee ett_aarroorraa@ @y.....cc oo..iinn

Singularize the letters above to send mail.