Has Implicit Int been disabled in the new C11 standard? What aboutother previously depreciated const

[Lord Voldermort]

As per subject.

Thanks.

Tom R.

 

[Lord Voldermort]

As per subject.

Thanks.

Tom R.

*BUMP*

Anyone able to answer this q?

 

[Ben Bacarisse]

*BUMP*

Anyone able to answer this q?

I'd have a go if I knew what you meant by "disabled". By the way, 18
minutes is not a long time on Usenet, and "bumping" a thread usually
just annoys people.

 

[Keith Thompson]

As per subject.

Thanks.

Tom R.

This is Usenet, not a web form or chat room. I suggest reading
some of the other articles posted here to get a feeling for the
best style.

Please put your question in the body of the post, not just in
the title.

Posting again after 18 minutes to "bump" the original post is not
useful. If you don't get a response after a day or so, it *might*
be time to worry.

Your actual questions, copied from the title:

Has Implicit Int been disabled in the new C11 standard?

Implicit int was removed from the language by the C99 standard.
(C11 did not restore it.) Many, probably most, C compilers still
support it as an extension (or just because they don't yet conform
to C99).

What about other previously depreciated constructions eg gets?

The gets function was removed completely.

I'm not aware of any other deprecated (note spelling) features that were
removed by C11. In particular, old-style function declarations and
definitions are still in the language.

You can get a draft, nearly equivalent to the final C11 standard, at
<http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1570.pdf>.

 

[Kaz Kylheku]

*BUMP*

Don't do this; Usenet is not a web bulletin board.

 

[Lord Voldermort]

This is Usenet, not a web form or chat room. I suggest reading some of
the other articles posted here to get a feeling for the best style.

Please put your question in the body of the post, not just in the title.

Posting again after 18 minutes to "bump" the original post is not
useful. If you don't get a response after a day or so, it *might* be
time to worry.

Your actual questions, copied from the title:


Implicit int was removed from the language by the C99 standard. (C11 did
not restore it.) Many, probably most, C compilers still support it as
an extension (or just because they don't yet conform to C99).


The gets function was removed completely.

I'm not aware of any other deprecated (note spelling) features that were
removed by C11. In particular, old-style function declarations and
definitions are still in the language.

You can get a draft, nearly equivalent to the final C11 standard, at
<http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1570.pdf>.

Thx for the info Keiht, sorry about breech of protocol - didnt see a way
to tell how many ppl are in this room so didnt know whether it was empty
or ppl just missed my post.

So is there any translation program then to take code for the previous
standard and upgrade it to work with C11 (replace gets by fgets etc)?

 

[Ben Bacarisse]

Thx for the info Keiht, sorry about breech of protocol - didnt see a way
to tell how many ppl are in this room so didnt know whether it was empty
or ppl just missed my post.

Have a read of this: http://en.wikipedia.org/wiki/Usenet to get an
overview.

So is there any translation program then to take code for the previous
standard and upgrade it to work with C11 (replace gets by fgets etc)?

In a way, yes. Your compiler can help if you if you ask for conformance
to a specific standard. That is likely to flag up problems, but it
won't fix them, of course. Some, like calls to gets, can't be fixed
automatically because the problem is that the function just does not
have enough information to do a safe job. Each call needs to be looked
at by someone who understands the code.

If the code is very old (pre-C90, often called K&R C) you'd have to have
a good reason to update it because the move to prototypes alters the way
a function is called in subtle ways. If in doubt, ask about that
specifically.

 

[Lord Voldermort]

Have a read of this: http://en.wikipedia.org/wiki/Usenet to get an
overview.

Didnt have time to read all that, but just flicking through I didnt see
anything about listing other people currently in this room/browsing the
forum/whatever you want to call it.

In a way, yes. Your compiler can help if you if you ask for conformance
to a specific standard. That is likely to flag up problems, but it
won't fix them, of course. Some, like calls to gets, can't be fixed
automatically because the problem is that the function just does not
have enough information to do a safe job. Each call needs to be looked
at by someone who understands the code.

If the code is very old (pre-C90, often called K&R C) you'd have to have
a good reason to update it because the move to prototypes alters the way
a function is called in subtle ways. If in doubt, ask about that
specifically.

Are you sure about this? Industry best practise is -- if possible, be
backwards compatable; if that can't be done, provide an automatic
updater. This has always been the case eg with Visual Basic.

It seems quite wreckless to update C while breaking existing programs and
leaving people to re-code manually!

 

[Keith Thompson]

Didnt have time to read all that, but just flicking through I didnt see
anything about listing other people currently in this room/browsing the
forum/whatever you want to call it.

There is no such feature. Don't think of this as a "room". A closer
metaphor might be distributed broadcast e-mail that anyone can read and
write.

I read your article on my own computer; there is no central server
that would know that. Your article was downloaded by the news
server I use (which happens to be news.eternal-september.org), but
that's just one of a number of news servers that share information
with each other. News servers transmit articles back and forth;
they don't track users. There is no central authority.

Usenet is older than the World Wide Web; early versions of it
didn't even use the Internet. (Modern implementations use the
NNTP protocol over TCP/IP.)

Hang around for a while; you'll get the hang of it.

Are you sure about this? Industry best practise is -- if possible, be
backwards compatable; if that can't be done, provide an automatic
updater. This has always been the case eg with Visual Basic.

It seems quite wreckless to update C while breaking existing programs and
leaving people to re-code manually!

The gets() function in particular is inherently unsafe. It should not
have been in the language in the first place, and programmers should
never have used it. That's why it was removed from C11. The only
programs that removing gets() might break were broken already, and those
programs *cannot* be fixed other than by manual recoding.

In any case, removing it from the standard doesn't magically remove it
from implementations. Implementers are still free to provide it as an
extension, or simply because they haven't yet fully implemented C11
(most C compilers haven't fully implemented C99 yet).

Note that some implementations already issue warnings for calls to
gets() (this particular warning is from the GNU linker):

c.c.text+0x52): warning: the `gets' function is dangerous and should not be used.

 

[Geoff]

It seems quite wreckless to update C while breaking existing programs and
leaving people to re-code manually!

Another aioe troll perhaps?

While it might be wreckless, it certainly isn't reckless to update the
C standard going forward. Revising the standard might break old
programs for compilation on new compilers but the medicine is more
beneficial than harmful.

 

[Stephen Sprunk]

Didnt have time to read all that,

Yet you're perfectly willing to waste dozens to thousands of potential
readers' time with your misunderstanding? How rude of you.

but just flicking through I didnt see anything about listing other
people currently in this room/browsing the forum/whatever you want to
call it.

That's because that's not how USENET works; it is not a live chat room.
Your message (slowly) spreads from server to server around the world,
and those who are interested will read it when they get around to
checking for new messages on their server, which might be hours, days or
even years later. Do not expect a response within minutes.

Incidentally, with modern threaded newsreaders, replying to your own
post does not "bump" it. And failed attempts to do so are more likely
to make readers dismiss your question rather than help you, so don't do
that.

Are you sure about this? Industry best practise is -- if possible, be
backwards compatable; if that can't be done, provide an automatic
updater. This has always been the case eg with Visual Basic.

That has not been the case for any programming language I've used, but I
was never forced to deal with VB.

The usual model is that features are deprecated (meaning they still
work, but you shouldn't use them, and compilers may complain if you do)
for a version or two before being officially removed.

It seems quite wreckless to update C while breaking existing programs and
leaving people to re-code manually!

ISO goes to great lengths to reduce the impact of this, and generally
only does so when the feature is so unsafe that leaving it in would be
more reckless than removing it.

Also, some compilers (eg. gcc) offer the ability to compile your program
according to a specific version of the standard, not just the latest
one. So, if your program is "broken" by a newer version of the
standard, eg. C11, you can just tell the compiler to use an older one,
eg. C89 or C99. You only need to fix your program if you want to take
advantage of the new features in the later version.

S

 

[Nick Keighley]

Thx

try to avoid text-speak

for the info Keiht,

try to spell peoples' names correctly

sorry about breech of protocol

that's "breach"- your spelling refers to trousers

- didnt see a way
to tell how many ppl are in this room

it isn't a room it's a usenet group

so didnt know whether it was empty
or ppl just missed my post.

<snip>

 

[Nick Keighley]

So is there any translation program then to take code for the previous
standard and upgrade it to work with C11 (replace gets by fgets etc)?

fgets() isn't a straight replacement for gets(). The end-of-line
handling is different. I also suspect the "translation program" would
have to read your mind in some cases in order to get the buffer size
right for fgets(). Do you use gets() a lot, or use programs that do?

 

[Keith Thompson]

On Sun, 19 Feb 2012 19:53:43 +0000 (UTC), Lord Voldermort


You've misunderstood Ben. The addition of function prototypes in the
language did not break existing programs. What may cause somewhat
subtle problems if you change your K&R style function declarations to
prototypes. There are case where the obvious prototype will cause
somewhat different behavior, and cases where the exact behavior cannot
be matched at all (although such are usually indicative of other
problems). But you can just leave your K&R style declarations as-is,
and nothing breaks.

Not quite.

Non-prototype declarations are still in the language, up to and
including the 2011 standard (and have been obsolescent since C89).
But C99 removed implicit int, which did break existing code
(though the fix was straightforward and fixed code could still be
compatible with pre-ANSI compilers). C11's removal of gets() also
broke existing code (though such code was already arguably broken).

 

[Ben Bacarisse]

fgets() isn't a straight replacement for gets(). The end-of-line
handling is different. I also suspect the "translation program" would
have to read your mind in some cases in order to get the buffer size
right for fgets(). Do you use gets() a lot, or use programs that do?

If you simply must get your gets-containing code to run today, you can use:

#define gets(s) (scanf("%[^\n]%*c", (s)) == 1 ? (s) : NULL)

but you should fix it tomorrow! (Not you personally, of course, but
"one" is sometimes too formal for Usenet).

 

[Keith Thompson]

fgets() isn't a straight replacement for gets(). The end-of-line
handling is different. I also suspect the "translation program" would
have to read your mind in some cases in order to get the buffer size
right for fgets(). Do you use gets() a lot, or use programs that do?

If you simply must get your gets-containing code to run today, you can use:

#define gets(s) (scanf("%[^\n]%*c", (s)) == 1 ? (s) : NULL)

but you should fix it tomorrow! (Not you personally, of course, but
"one" is sometimes too formal for Usenet).

If you simply must get such code running *today*, you can just
leave the gets() call in place. I don't believe there are yet any
hosted C implementations that don't provide it.

 

[Quentin Pope]

fgets() isn't a straight replacement for gets(). The end-of-line
handling is different. I also suspect the "translation program" would
have to read your mind in some cases in order to get the buffer size
right for fgets(). Do you use gets() a lot, or use programs that do?

If you simply must get your gets-containing code to run today, you can
use:

#define gets(s) (scanf("%[^\n]%*c", (s)) == 1 ? (s) : NULL)

but you should fix it tomorrow! (Not you personally, of course, but
"one" is sometimes too formal for Usenet).

Does that mean that the identifier gets has been returned to the user's
namespace? That sounds like a recipe for confusion if people try to mix
old code with C11 code that uses gets for something unrelated to the
original function.

//QP

 

[James Kuyper]

On 02/21/2012 02:51 PM, Quentin Pope wrote:
....

Does that mean that the identifier gets has been returned to the user's
namespace? ...

Yes. In the new standard, gets() is only mentioned in two places:
Forward: as something that has been removed.
Footnote 440: as something to compare gets_s() to.

Therefore, it is no longer counts as one of the identifier referred to
by 7.1.3p1.

... That sounds like a recipe for confusion if people try to mix
old code with C11 code that uses gets for something unrelated to the
original function.

True, but all of the other reserved identifiers are either generically
reserved to implementation for certain purposes, specifically reserved
for current standard-defined uses, or specifically reserved in
anticipation of future standard-defined uses. There's no precedent for
adding a specific obsolete identifier to the reserved list - and this
version of the standard establishes a precedent for not doing so.

For the next decade or two, any decent C2011+ compiler will probably
have an option that warns about user-provided definitions of 'gets', but
I wouldn't recommend counting on that in the long-term.

 

[Jens Gustedt]

Hello,

Am 02/21/2012 09:11 PM, schrieb James Kuyper:

On 02/21/2012 02:51 PM, Quentin Pope wrote:
...

Yes. ...

For the next decade or two, any decent C2011+ compiler will probably
have an option that warns about user-provided definitions of 'gets', but
I wouldn't recommend counting on that in the long-term.

Probably this is just something that nobody thought about, since it
never happened before. Sounds like a good point for a DR.

Jens

 

[Keith Thompson]

Am 02/21/2012 09:11 PM, schrieb James Kuyper:

Probably this is just something that nobody thought about, since it
never happened before. Sounds like a good point for a DR.

It's unlikely that nobody thought about it. I seem to recall it being
discussed in comp.std.c.