Re: proposed Opengroup action for c99 command (XCU ERN 76)

> > Not really a problem for a number of reasons. First, it's LC_CTYPE > > you're thinking of. Second, the narrow character set can only be 16-bits > > wide if "char" is 16-bits. Thirdly, if the character set that LC_CTYPE > > selects isn't superset of the POSIX portable character set then resul

Re: proposed Opengroup action for c99 command (XCU ERN 76)

[EMAIL PROTECTED] (Ross Ridge) writes: > >The POSIXy way to do that would be to refer to the LC_CHARSET > >environment variable, but then consider > > > >LC_CHARSET=UTF-16 c99 foo.c > > > >where 'foo.c' is in UTF-16 and contains '#include ', > > Not really a problem for a number of reasons. Firs

Re: proposed Opengroup action for c99 command (XCU ERN 76)

>The POSIXy way to do that would be to refer to the LC_CHARSET >environment variable, but then consider > >LC_CHARSET=UTF-16 c99 foo.c > >where 'foo.c' is in UTF-16 and contains '#include ', Not really a problem for a number of reasons. First, it's LC_CTYPE you're thinking of. Second, the narrow

Re: proposed Opengroup action for c99 command (XCU ERN 76)

Paul Eggert <[EMAIL PROTECTED]> writes: > Thanks, everybody, for writing about this. > > The standardization process is one of consensus, and if the GCC > developers find some areas of disagreement here I think it unlikely > that the other POSIX implementers will agree with the proposed action. >

Re: proposed Opengroup action for c99 command (XCU ERN 76)

[EMAIL PROTECTED] (Joseph S. Myers) wrote on 16.09.05 in <[EMAIL PROTECTED]>: > C++ requires (A) and provides examples of valid programs where it can be > told whether a normalisation of UCNs is part of the implementation-defined > phase 1 transformation. As I gave in a previous discussion, > >

Re: proposed Opengroup action for c99 command (XCU ERN 76)

Paul Eggert writes: > Would this weaker action pose an undue burden on GCC? My sense from > the discussion is "no", but I'd like to double-check with the experts I'd say "no", but I think the experts might see it as posing no burden at all on GCC. The burden would be on whomever wants to use GCC

Re: proposed Opengroup action for c99 command (XCU ERN 76)

"Zack Weinberg" <[EMAIL PROTECTED]> writes: [...] | Also: why do you care so much about this corner case? I only care from the | implementation perspective, since I doubt it matters to any real software that | GCC might compile. I'm pointing out an approach to the problem which would | avoid ha

Re: proposed Opengroup action for c99 command (XCU ERN 76)

Gabriel Dos Reis said: [...] > Good. It seems to me like those who would be spending a great deal of > time and money are not sufficiently convinced by your arguments. > Consequently, it appears that they are not in position to explain your > strong opinion to the committees -- personally, I'm not

Re: proposed Opengroup action for c99 command (XCU ERN 76)

Mike Stump <[EMAIL PROTECTED]> writes: | On Sep 17, 2005, at 3:33 PM, Gabriel Dos Reis wrote: | > C++98 came before C99, so who diverged from whom? | | You seem to not not how the C++ standard was made. Thank you very much. | In fact, it come before C99, like it or not. Oh really? What did I

Re: proposed Opengroup action for c99 command (XCU ERN 76)

On Sep 17, 2005, at 3:33 PM, Gabriel Dos Reis wrote: C++98 came before C99, so who diverged from whom? You seem to not not how the C++ standard was made. In fact, it come before C99, like it or not. The intention was that C++ would come up with a follow on standard that tracked C99, in ne

Re: proposed Opengroup action for c99 command (XCU ERN 76)

"Zack Weinberg" <[EMAIL PROTECTED]> writes: | Gabriel Dos Reis said: | > "Zack Weinberg" <[EMAIL PROTECTED]> writes: | > | > | Gabriel Dos Reis said: | > | > C++98 came before C99, so who diverged from whom? | > | | > | It doesn't matter. | > | > Yet, you're you were construeing it as an argument

Re: proposed Opengroup action for c99 command (XCU ERN 76)

Gabriel Dos Reis said: > "Zack Weinberg" <[EMAIL PROTECTED]> writes: > > | Gabriel Dos Reis said: > | > C++98 came before C99, so who diverged from whom? > | > | It doesn't matter. > > Yet, you're you were construeing it as an argument to support your position. I'm only bringing up the divergence

Re: proposed Opengroup action for c99 command (XCU ERN 76)

"Zack Weinberg" <[EMAIL PROTECTED]> writes: | Gabriel Dos Reis said: | > "Zack Weinberg" <[EMAIL PROTECTED]> writes: | > | When the standard is arguably buggy -- if nothing else, it diverges from C | > | > C++98 came before C99, so who diverged from whom? | | It doesn't matter. Yet, you're you w

Re: proposed Opengroup action for c99 command (XCU ERN 76)

Gabriel Dos Reis said: > "Zack Weinberg" <[EMAIL PROTECTED]> writes: > | When the standard is arguably buggy -- if nothing else, it diverges from C > > C++98 came before C99, so who diverged from whom? It doesn't matter. The divergence should be resolved in favor of whichever standard has it righ

Re: proposed Opengroup action for c99 command (XCU ERN 76)

"Zack Weinberg" <[EMAIL PROTECTED]> writes: | Joseph S. Myers said: | > On Fri, 16 Sep 2005, Zack Weinberg wrote: | >> I am with Joe Buck in the opinion that even a 1% performance penalty for | >> implementing (A) [or (B)] would be too much -- I suggest this be fixed by | >> convincing the C++ com

Re: proposed Opengroup action for c99 command (XCU ERN 76)

Joseph S. Myers said: > On Fri, 16 Sep 2005, Zack Weinberg wrote: >> I am with Joe Buck in the opinion that even a 1% performance penalty for >> implementing (A) [or (B)] would be too much -- I suggest this be fixed by >> convincing the C++ committee to allow (C) and not just by phase 1 >> transfor

Re: proposed Opengroup action for c99 command (XCU ERN 76)

On Fri, 16 Sep 2005, Zack Weinberg wrote: > Especially for C++ which constructs a cpp_token array (sort of) representing > the entire translation unit, it is desirable to make cpp_token *smaller* -- > and it would be relatively easy to win back that 'whole word not used in the > case of identifier

Re: proposed Opengroup action for c99 command (XCU ERN 76)

On Fri, 16 Sep 2005, Ross Ridge wrote: > Joe Buck writes: > > To me, even a 1% performance hit to fix this would be excessive. > > I think any performance hit to support UCNs or extended characters outside > of strings and comments is undesirable. GCC should have an option like > "-trigraphs" fo

Re: proposed Opengroup action for c99 command (XCU ERN 76)

Thanks, everybody, for writing about this. The standardization process is one of consensus, and if the GCC developers find some areas of disagreement here I think it unlikely that the other POSIX implementers will agree with the proposed action. Hence I am thinking of weakening it. Currently the

Re: proposed Opengroup action for c99 command (XCU ERN 76)

Joe Buck writes: > To me, even a 1% performance hit to fix this would be excessive. I think any performance hit to support UCNs or extended characters outside of strings and comments is undesirable. GCC should have an option like "-trigraphs" for the few programs that need this feature.

Re: proposed Opengroup action for c99 command (XCU ERN 76)

Joe Buck <[EMAIL PROTECTED]> writes: | On Fri, Sep 16, 2005 at 08:58:12PM +0200, Gabriel Dos Reis wrote: | > Joe Buck <[EMAIL PROTECTED]> writes: | > | > | To me, even a 1% performance hit to fix this would be excessive. | > | > My opinion is that is an excessive statement. | | Really, Gaby? C

Re: proposed Opengroup action for c99 command (XCU ERN 76)

On Fri, Sep 16, 2005 at 08:58:12PM +0200, Gabriel Dos Reis wrote: > Joe Buck <[EMAIL PROTECTED]> writes: > > | To me, even a 1% performance hit to fix this would be excessive. > > My opinion is that is an excessive statement. Really, Gaby? Consider that there are hundreds of other open bugs. Wo

Re: proposed Opengroup action for c99 command (XCU ERN 76)

[I apologize for breaking the thread; I am currently stuck using a web-mail client that does not permit manual insertion of References: headers. Please don't take this comment as a sign that I am resuming participation in GCC development in general.] Joseph Myers: > There are plenty of spare bits

Re: proposed Opengroup action for c99 command (XCU ERN 76)

Joe Buck <[EMAIL PROTECTED]> writes: | To me, even a 1% performance hit to fix this would be excessive. My opinion is that is an excessive statement. -- Gaby

Re: proposed Opengroup action for c99 command (XCU ERN 76)

On 16/09/2005, at 5:12 AM, Joseph S. Myers wrote: On Fri, 16 Sep 2005, Geoffrey Keating wrote: What this means in practise, I think, is that the structure that represents a token, 'struct cpp_token' will grow from 16 bytes to 20 bytes, which makes it 2 cache lines rather than 1, and a subseq

Re: proposed Opengroup action for c99 command (XCU ERN 76)

On Fri, 16 Sep 2005, Geoffrey Keating wrote: > > Adding salt to the wound, of course, is that for C the only difference > > between an (A) or (B) and a (C) implementation is that a (C) > > implementation is less expressive: there are some programs, all of > > which are erroneous and require a diag

Re: proposed Opengroup action for c99 command (XCU ERN 76)

Ross Ridge wrote: > Thinking semantically is irrelevent because the question isn't whether GCC > conforms to C99 or POSIX. It clearly doesn't. GCC fails the as-if rule. > The question is one of implementation burden, which can only be answered > by examining GCC's implementation. Robert Dewar w

Re: proposed Opengroup action for c99 command (XCU ERN 76)

On Fri, 16 Sep 2005, Geoffrey Keating wrote: > What this means in practise, I think, is that the structure that > represents a token, 'struct cpp_token' will grow from 16 bytes to 20 > bytes, which makes it 2 cache lines rather than 1, and a subsequent > memory use increase and compiler performanc

Re: proposed Opengroup action for c99 command (XCU ERN 76)

Paul Eggert <[EMAIL PROTECTED]> writes: Hi Paul, > I proposed to insert the following paragraph after XCU page 213 line > 8366 (i.e, at the end of the INPUT FILES section of the c99 spec > ): > >It is implementation-defined wh

Re: proposed Opengroup action for c99 command (XCU ERN 76)

Ross Ridge wrote: Thinking semantically is irrelevent because the question isn't whether GCC conforms to C99 or POSIX. It clearly doesn't. GCC fails the as-if rule. The question is one of implementation burden, which can only be answered by examining GCC's implementation. Once again we are n

Re: proposed Opengroup action for c99 command (XCU ERN 76)

> You are thinking operationally, when you should think semantically. > Remember that as-if applies here. The rules as stated give ways to > achieve certain effects, the question is not whether we are following > the operational rules, but whether we are following the effects. Thinking semantical

Re: proposed Opengroup action for c99 command (XCU ERN 76)

Ross Ridge wrote: > >Well, maybe I'm missing something, but it never converts input characters > >to UCNs so that means it doesn't do (A) or (B), and the only thing it > >converts to wide characters are wide string literals, so it doesn't do > >(C). On Thu, Sep 15, 2005 at 07:24:47AM -0400, Rober

Re: proposed Opengroup action for c99 command (XCU ERN 76)

On Wed, 14 Sep 2005, Paul Eggert wrote: > So my question is: Is it a burden on GCC to require interpretation (B)? Yes, but my position remains that we *should* aim to implement (B) and this is a proper burden to impose. For how the interpretations can be distinguished, see bug 9449 comments 21

Re: proposed Opengroup action for c99 command (XCU ERN 76)

Ross Ridge wrote: Well, maybe I'm missing something, but it never converts input characters to UCNs so that means it doesn't do (A) or (B), and the only thing it converts to wide characters are wide string literals, so it doesn't do (C). You are thinking operationally, when you should think se

Re: proposed Opengroup action for c99 command (XCU ERN 76)

> > A. Convert everything to UCNs in basic source characters as soon > > as possible, that is, in translation phase 1. (This is what > > C++ requires, apparently.) > > > > B. Use native encodings where possible, UCNs otherwise. > > > > C. Convert everything to wide character

Re: proposed Opengroup action for c99 command (XCU ERN 76)

I am the opposite of an expert on this topic. But in fact gcc does appear to have code related to (A), (B), and (C). I repeat those choices here from Paul's original e-mail: A. Convert everything to UCNs in basic source characters as soon as possible, that is, in translation phase 1

Re: proposed Opengroup action for c99 command (XCU ERN 76)

[EMAIL PROTECTED] (Ross Ridge) writes: > > I was not asking the general question, I was asking how it fails > > to conform wrt the particular technical issue at hand. > > Since GCC doesn't have any code that does (A), (B), or (C) it doesn't > place a burden on GCC to require it to do (B). That's

Re: proposed Opengroup action for c99 command (XCU ERN 76)

> I was not asking the general question, I was asking how it fails > to conform wrt the particular technical issue at hand. Since GCC doesn't have any code that does (A), (B), or (C) it doesn't place a burden on GCC to require it to do (B). That's sufficient to answer the techinical issue at hand

Re: proposed Opengroup action for c99 command (XCU ERN 76)

Ross Ridge wrote: GCC doesn't claim C99 conformance. The following URL lists a number of different areas in which GCC is known not to conform: I was not asking the general question, I was asking how it fails to conform wrt the particular technical issue at hand.

Re: proposed Opengroup action for c99 command (XCU ERN 76)

Ross Ridge wrote: > GCC doesn't use (A), (B) or (C). GCC doesn't conform to C99 and > any implementation of "c99" that uses GCC would presumably also be > non-conforming. Robert Dewar wrote: > What exactly is the observable non-conformance? Ross Ridge wrote: > GCC doesn't claim C99 conformance

Re: proposed Opengroup action for c99 command (XCU ERN 76)

Paul Eggert wrote:- > Here's the problem. Currently, POSIX places almost no requirements on > how c99 transforms the physical source file into C source-language > characters. For example, c99 is free to treat CR as LF, ignore > trailing white space, convert tabs to spaces, or even (perversely) >

Re: proposed Opengroup action for c99 command (XCU ERN 76)

[EMAIL PROTECTED] (Ross Ridge) writes: > Ross Ridge wrote: > > GCC doesn't use (A), (B) or (C). GCC doesn't conform to C99 and > > any implementation of "c99" that uses GCC would presumably also be > > non-conforming. > > Robert Dewar wrote: > > What exactly is the observable non-conformance? >

Re: proposed Opengroup action for c99 command (XCU ERN 76)

Ross Ridge wrote: > GCC doesn't use (A), (B) or (C). GCC doesn't conform to C99 and > any implementation of "c99" that uses GCC would presumably also be > non-conforming. Robert Dewar wrote: > What exactly is the observable non-conformance? GCC doesn't claim C99 conformance. The following URL

Re: proposed Opengroup action for c99 command (XCU ERN 76)

Ross Ridge wrote: GCC doesn't use (A), (B) or (C). GCC doesn't conform to C99 and any implementation of "c99" that uses GCC would presumably also be non-conforming. What exactly is the observable non-conformance?

Re: proposed Opengroup action for c99 command (XCU ERN 76)

Paul Eggert wrote: >So my question is: Is it a burden on GCC to require interpretation (B)? > >My understanding is that GCC already uses (B), and that the answer is >"no, it's no problem", but if I'm wrong please let me know. GCC doesn't use (A), (B) or (C). GCC doesn't conform to C99 and any imp

Re: proposed Opengroup action for c99 command (XCU ERN 76)

On Wed, Sep 14, 2005 at 01:50:19PM -0700, Paul Eggert wrote: > In response Joseph S. Myers pointed out that this action would require > c99 to use interpretation B of section 5.2.1 (page 20) of the C99 Rationale > . > The Rationale s

proposed Opengroup action for c99 command (XCU ERN 76)

I recently proposed to the Open Group an action that would modify the POSIX specification for the c99 command that is often implemented using GCC. I thought the action would not affect GCC's conformance, but Joseph S. Myers raised the issue of UCNs and multibyte characters and I'd like to double-c