Subject: bin/21970: printf(1) breaks when format begins with "-"
To: None <gnats-bugs@gnats.netbsd.org>
From: Alan Barrett <apb@cequrux.com>
List: netbsd-bugs
Date: 06/23/2003 18:10:08
>Number: 21970
>Category: bin
>Synopsis: printf(1) breaks when format begins with "-"
>Confidential: no
>Severity: serious
>Priority: medium
>Responsible: bin-bug-people
>State: open
>Class: sw-bug
>Submitter-Id: net
>Arrival-Date: Mon Jun 23 16:11:00 UTC 2003
>Closed-Date:
>Last-Modified:
>Originator: Alan Barrett
>Release: NetBSD 1.6T
>Organization:
not much
>Environment:
System: NetBSD 1.6T
Architecture: i386
Machine: i386
>Description:
printf(1) is documented as not taking any options. The
first arg is supposed to be a format string.
However, if the format string begins with "-" then printf(1)
incorrectly treats it like an option.
>How-To-Repeat:
1. The following command should output "-foo<newline>".
Instead, it produces an error.
$ printf "-%s\n" "foo"
sh: unknown option -- f
usage: printf format [arg ...]
2. The following command should output "--foo<newline>".
Instead, it produces an error.
$ printf "--%s\n" "foo"
sh: unknown option -- -
usage: printf format [arg ...]
3. The following command should output "-" (without a newline),
and it works correctly.
$ printf "-"
-$
4. The following command should output "--" (without a newline).
Instead, it produces an error.
$ printf "--"
printf: usage: printf format [arguments]
5. The following command should treat the first arg as a format string;
so it should output "--" (without a newline), and it should ignore
the second and third args. Instead, it ignores the first arg, treats
the second arg as a format string, and interpolates the third arg as
a parameter in the format string.
$ printf -- "--%s\n" "foo"
--foo
>Fix:
To make the behaviour match the documentation, remove the getopt() loop
at the top of src/bin/printf/printf.c
Alternatively, if the observed behaviour is actually the desired
behaviour, then fix the documentation to: (1) mention the special
treatment of "--"; (2) mention that the format string may not begin with
"-", unless it is preceded by a special "--" arg.
>Release-Note:
>Audit-Trail:
>Unformatted: