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[bug-gnulib] Re: bugs in regexp.c
From: |
Paul Eggert |
Subject: |
[bug-gnulib] Re: bugs in regexp.c |
Date: |
Fri, 18 Mar 2005 13:23:41 -0800 |
User-agent: |
Gnus/5.1006 (Gnus v5.10.6) Emacs/21.4 (gnu/linux) |
Sam Steingold <address@hidden> writes:
> I think it is a good practice to treat undefined behavior as an
> error.
That may be, but in that case the test cases assuming a particular
extension tof POSIX, and the test cases therefore will not be portable
to all POSIX implementations. I suspect that in some cases the
regexp.c behavior is compatible with traditional UNIX, which did not
always treat undefined behavior as an error; changing it might break
applications assuming the traditional UNIX behavior.
> (regcomp (&r, "$*", REG_EXTENDED) != 0)
Ah, OK, I see now. That has undefined behavior. "$*" is a valid BRE,
but it is not a valid ERE.
<http://www.opengroup.org/onlinepubs/009695399/basedefs/xbd_chap09.html#tag_09_04_06>
defines the behavior of "*" only if it is preceded by "an ERE matching
a single character or an ERE enclosed in parentheses". But "$" is not
such an ERE.