Re: getopt.3 bugs section
On Jan 9, 2021 7:07 AM, Christian Weisgerber wrote: Edgar Pettijohn: > In the BUGS section for the getopt(3) manual it mentions not using > single digits for options. I know spamd uses -4 and -6 there are > probably others. Should they be changed? Or is the manual mistaken? You misunderstand. The manual warns against the use of digits to pass numerical arguments. This usage exists in some historical cases, e.g. "nice -10" where <10> is the number 10. The use of digits as flags characters, like -4 or -6 to indicate IPv4 or IPv6, is perfectly fine. -- Christian "naddy" Weisgerber na...@mips.inka.de Makes sense. I think it would have been clearer if it just had an example of what not to do instead of how to do the wrong thing right. Thanks, Edgar
Re: getopt.3 bugs section
On Sat, Jan 09, 2021 at 02:07:32PM +0100, Christian Weisgerber wrote: > Edgar Pettijohn: > > > In the BUGS section for the getopt(3) manual it mentions not using > > single digits for options. I know spamd uses -4 and -6 there are > > probably others. Should they be changed? Or is the manual mistaken? > > You misunderstand. The manual warns against the use of digits to > pass numerical arguments. This usage exists in some historical > cases, e.g. "nice -10" where <10> is the number 10. > > The use of digits as flags characters, like -4 or -6 to indicate > IPv4 or IPv6, is perfectly fine. If you want to change this, it seems best to point to existing good and bad examples. Good: - using digits as flags, e.g. for IPv4 vs IPv6 support Bad: - using digits as numbers, e.g. nice(1), tail(1) historic use. Recommendation to avoid bad use: -n Joerg
Re: getopt.3 bugs section
On Sat, Jan 09 2021, Christian Weisgerber wrote: > Edgar Pettijohn: > >> In the BUGS section for the getopt(3) manual it mentions not using >> single digits for options. I know spamd uses -4 and -6 there are >> probably others. Should they be changed? Or is the manual mistaken? > > You misunderstand. The manual warns against the use of digits to > pass numerical arguments. This usage exists in some historical > cases, e.g. "nice -10" where <10> is the number 10. IMO giving a *number* as an example would make things clearer. Index: getopt.3 === RCS file: /d/cvs/src/lib/libc/stdlib/getopt.3,v retrieving revision 1.46 diff -u -p -p -u -r1.46 getopt.3 --- getopt.34 Jan 2016 19:43:13 - 1.46 +++ getopt.39 Jan 2021 13:39:06 - @@ -326,7 +326,7 @@ It is possible to handle digits as optio This allows .Fn getopt to be used with programs that expect a number -.Pq Dq Li \-3 +.Pq Dq Li \-389 as an option. This practice is wrong, and should not be used in any current development. It is provided for backward compatibility Other ideas for improvement: - give a real life example Index: getopt.3 === RCS file: /d/cvs/src/lib/libc/stdlib/getopt.3,v retrieving revision 1.46 diff -u -p -p -u -r1.46 getopt.3 --- getopt.34 Jan 2016 19:43:13 - 1.46 +++ getopt.39 Jan 2021 13:44:29 - @@ -326,7 +326,7 @@ It is possible to handle digits as optio This allows .Fn getopt to be used with programs that expect a number -.Pq Dq Li \-3 +.Pq Dq Li nice \-10 program as an option. This practice is wrong, and should not be used in any current development. It is provided for backward compatibility - move this warning to CAVEATS, since it's not a bug Index: getopt.3 === RCS file: /d/cvs/src/lib/libc/stdlib/getopt.3,v retrieving revision 1.46 diff -u -p -p -u -r1.46 getopt.3 --- getopt.34 Jan 2016 19:43:13 - 1.46 +++ getopt.39 Jan 2021 13:47:08 - @@ -309,24 +309,12 @@ The .Fn getopt function appeared in .Bx 4.3 . -.Sh BUGS -The -.Fn getopt -function was once specified to return -.Dv EOF -instead of \-1. -This was changed by -.St -p1003.2-92 -to decouple -.Fn getopt -from -.In stdio.h . -.Pp +.Sh CAVEATS It is possible to handle digits as option letters. This allows .Fn getopt to be used with programs that expect a number -.Pq Dq Li \-3 +.Pq Dq Li nice \-10 program as an option. This practice is wrong, and should not be used in any current development. It is provided for backward compatibility @@ -361,3 +349,15 @@ while ((ch = getopt(argc, argv, "0123456 prevoptind = optind; } .Ed +.Sh BUGS +The +.Fn getopt +function was once specified to return +.Dv EOF +instead of \-1. +This was changed by +.St -p1003.2-92 +to decouple +.Fn getopt +from +.In stdio.h . Would the mention of EOF vs -1 fit better in HISTORY or CAVEATS too? -- jca | PGP : 0x1524E7EE / 5135 92C1 AD36 5293 2BDF DDCC 0DFA 74AE 1524 E7EE
Re: getopt.3 bugs section
Edgar Pettijohn: > In the BUGS section for the getopt(3) manual it mentions not using > single digits for options. I know spamd uses -4 and -6 there are > probably others. Should they be changed? Or is the manual mistaken? You misunderstand. The manual warns against the use of digits to pass numerical arguments. This usage exists in some historical cases, e.g. "nice -10" where <10> is the number 10. The use of digits as flags characters, like -4 or -6 to indicate IPv4 or IPv6, is perfectly fine. -- Christian "naddy" Weisgerber na...@mips.inka.de
Re: getopt.3 bugs section
On Fri, Jan 08, 2021 at 05:29:31PM -0600, Edgar Pettijohn wrote: > In the BUGS section for the getopt(3) manual it mentions not using > single digits for options. I know spamd uses -4 and -6 there are > probably others. Should they be changed? Or is the manual mistaken? > That section seems ambiguous (especially in light of your post) on whether using digits is wrong, or abusing digit support for multi-digit number option support is wrong. But I think the intention is the latter. FWIW, POSIX explicitly permits digits: Guideline 3: Each option name should be a single alphanumeric character (the alnum character classification) from the portable character set. The -W (capital-W) option shall be reserved for vendor options. Multi-digit options should not be allowed. https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap12.html#tag_12_02 Guideline 3 applies to getopt(3) because, The getopt() function... shall follow Utility Syntax Guidelines 3, 4, 5, 6, 7, 9, and 10 in XBD Utility Syntax Guidelines. https://pubs.opengroup.org/onlinepubs/9699919799/functions/getopt.html
getopt.3 bugs section
In the BUGS section for the getopt(3) manual it mentions not using single digits for options. I know spamd uses -4 and -6 there are probably others. Should they be changed? Or is the manual mistaken? Edgar
