July 2005 - Darwin-dev - lists.apple.com

DVD writer example program
by Peter H.M. Brooks 04 Jul '05

04 Jul '05

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com Importance: Normal User-agent: SquirrelMail/1.4.4 There's a useful example of a CD-R program in the developer directory - it shows how to write the three different formats. I've also seen the include file to set things up to recognise the various DVD types. I'd really like it if there was a similarly simple example program for writing to a DVD-R. I'd like to produce an automatic incremental backup script and an example program would make this a very simple matter! Any assistance would be gratefully received! _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… This email sent to site_archiver(a)lists.apple.com

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Re: fmtcheck.c
by Jordan K. Hubbard 03 Jul '05

03 Jul '05

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… This email sent to site_archiver(a)lists.apple.com

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Re: fmtcheck.c
by Steve Checkoway 02 Jul '05

02 Jul '05

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com On Jul 2, 2005, at 2:03 PM, Steve Checkoway wrote: - Steve _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… This email sent to site_archiver(a)lists.apple.com I'll fix my code shortly. I fixed the code to follow the Single Unix Specification. The new code is at the same URL as before: http://www.cs.washington.edu/homes/steve/fmtcheck.c One of my test cases was explicitly depending on the behavior as described in the BSD man page. I fixed it ("%2$f%hd%1$D" became "%2$f% 3$hd%1$D"). The new file replaced the old at http://www.cs.washington.edu/homes/steve/fcheck.c smime.p7s

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Re: fmtcheck.c
by Steve Checkoway 02 Jul '05

02 Jul '05

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com On Jul 2, 2005, at 1:14 PM, Markus Hitter wrote: I'll fix my code shortly. - Steve _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… This email sent to site_archiver(a)lists.apple.com 'f' means float. %f == %lf is a implementation detail of the Darwin. This wasn't always the case. Perhaps it wasn't always the case but the ISO/IEC 9899:1999 (E) standard says of the l(ell) length modifier: Specifies that a following d, i, o, u, x or X conversion specifier applies to a long int or unsigned long int argument; that a following n conversion specifier applies to a pointer to a long int argument; that a following c conversion specifier applies to a wint_t argument; that a following s conversion specifier applies to a pointer to a wchar_t argument; or has no effect on a following a, A, e, E, f, F, g, or G conversion specifier. The linux man page for printf(3) says that the C99 standard does not include the style using '$'--and indeed, I could not find it--but says that it comes from the Single Unix Specification. On this point, the Linux and BSD man pages differ. The BSD man page says, "If unaccessed arguments in the format string are interspersed with ones that are accessed the results will be indeterminate." The Linux man page says, "If the style using ‘$’ is used, it must be used throughout for all conversions taking an argument and all width and precision arguments, but it may be mixed with ‘%%’ formats which do not consume an argument. There may be no gaps in the numbers of arguments specified using ‘$’; for example, if arguments 1 and 3 are specified, argument 2 must also be specified somewhere in the format string." It's clear that the Linux man page has a strong requirement since "%2 $d %d %1$d" would be allowed by the BSD page, it would not be allowed by the Linux page. ("%2$*d" is disallowed by both man pages.) Given the discrepancy, the only thing to do was to check the Single Unix Specification (http://www.opengroup.org/onlinepubs/007908799/xsh/ fprintf.html) which has this to say: The format can contain either numbered argument specifications (that is, %n$ and *m$), or unnumbered argument specifications (that is, % and *), but normally not both. The only exception to this is that %% can be mixed with the %n$ form. The results of mixing numbered and unnumbered argument specifications in a format string are undefined. When numbered argument specifications are used, specifying the Nth argument requires that all the leading arguments, from the first to the (N-1)th, are specified in the format string. This appears to agree with the Linux man page with the exception that it says that the only exception to the rule about not mixing argument types is mixing %n$ with %% but does not say anything about mixing *m $ with %%. I can only assume that that omission is unintentional and that the latter is allowed. smime.p7s

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Re: fmtcheck.c
by seebs＠plethora.net 02 Jul '05

02 Jul '05

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com In message <0EE40CBC-07B9-495A-96AD-16B8844F7628(a)jump-ing.de>, Markus Hitter wr ites: >'f' means float. %f == %lf is a implementation detail of the Darwin. >This wasn't always the case. Can you name a counterexample? I certainly can't. %f has meant double since the dawn of time, because variadic functions have always had to use the default promotions, so there's no way to pass an unmunged float to them. -s _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… This email sent to site_archiver(a)lists.apple.com

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Re: fmtcheck.c
by Markus Hitter 02 Jul '05

02 Jul '05

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com Am 02.07.2005 um 11:07 schrieb Peter Seebach: Again, from the man page: Modifier a, A, e, E, f, F, g, G l (ell) double (ignored, same behavior as without it) L long double Markus - - - - - - - - - - - - - - - - - - - Dipl. Ing. Markus Hitter http://www.jump-ing.de/ _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… The man page is a little misleading on that. 'f' means double, 'l' is not a modifier, on any of the floating point types. 'f' means float. %f == %lf is a implementation detail of the Darwin. This wasn't always the case. This email sent to site_archiver(a)lists.apple.com

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Re: fmtcheck.c
by Steve Checkoway 02 Jul '05

02 Jul '05

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… This email sent to site_archiver(a)lists.apple.com smime.p7s

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Re: fmtcheck.c
by Jordan K. Hubbard 02 Jul '05

02 Jul '05

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… This email sent to site_archiver(a)lists.apple.com

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Re: fmtcheck.c
by seebs＠plethora.net 02 Jul '05

02 Jul '05

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com In message <52254B38-0B27-4C33-905D-7C8ACA97F25E(a)cs.washington.edu>, Steve Chec koway writes: >On Jul 1, 2005, at 7:36 PM, Peter Seebach wrote: > >> I have no spec for the $ syntax. > > From the printf(3) man page: > > An optional field, consisting of a decimal digit string >followed by a > $, specifying the next argument to access. If this field >is not pro- > vided, the argument following the last argument accessed >will be > used. Arguments are numbered starting at 1. If unaccessed >arguments > in the format string are interspersed with ones that are >accessed the > results will be indeterminate. Hmm. I suppose it makes sense to extend fmtcheck, if printf is to be extended. >> Er, what's %lf? %f takes a double, %Lf takes a long double. I don't >> know of any purpose for %lf. >Again, from the man page: > > Modifier a, A, e, E, f, F, g, G > l (ell) double (ignored, same behavior as without it) > L long double >It's supported. As for its utility... The man page is a little misleading on that. 'f' means double, 'l' is not a modifier, on any of the floating point types. >Actually, I misspoke earlier when I said that the version in NetBSD >was the same as the one in Darwin. The one in NetBSD is newer in >that it correctly ignores the ' flag while the one in Darwin does not. It's probably more actively maintained; the ideal thing might be to get it debugged there, then import it "to track improvements in NetBSD", because it'll be politically easier. :) -s _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… This email sent to site_archiver(a)lists.apple.com

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Re: fmtcheck.c
by Steve Checkoway 02 Jul '05

02 Jul '05

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com On Jul 1, 2005, at 7:36 PM, Peter Seebach wrote: >From the printf(3) man page: Er, what's %lf? %f takes a double, %Lf takes a long double. I don't know of any purpose for %lf. Again, from the man page: Modifier a, A, e, E, f, F, g, G l (ell) double (ignored, same behavior as without it) L long double It's supported. As for its utility... Perhaps I'll do that. _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… This email sent to site_archiver(a)lists.apple.com I have no spec for the $ syntax. An optional field, consisting of a decimal digit string followed by a $, specifying the next argument to access. If this field is not pro- vided, the argument following the last argument accessed will be used. Arguments are numbered starting at 1. If unaccessed arguments in the format string are interspersed with ones that are accessed the results will be indeterminate. It would probably be worth filing a bug report with Alan Briggs, who has a specific reason to care whether fmtcheck() is buggy. Actually, I misspoke earlier when I said that the version in NetBSD was the same as the one in Darwin. The one in NetBSD is newer in that it correctly ignores the ' flag while the one in Darwin does not. - Steve smime.p7s

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