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Re: [PATCH 1/2] posixoptions.7: Expand XSI Options groups.
- From: Zack Weinberg <zackw at panix dot com>
- To: "Michael Kerrisk (man-pages)" <mtk dot manpages at gmail dot com>
- Cc: Rical Jasan <rj at 2c3t dot io>, "Carlos O'Donell" <carlos at redhat dot com>, "linux-man at vger dot kernel dot org" <linux-man at vger dot kernel dot org>, Florian Weimer <fweimer at redhat dot com>, GNU C Library <libc-alpha at sourceware dot org>
- Date: Sun, 15 Apr 2018 21:17:57 -0400
- Subject: Re: [PATCH 1/2] posixoptions.7: Expand XSI Options groups.
- References: <2d6c47e9-0f34-c828-916e-a45fbf90f837@redhat.com> <4d8d0ca1-a612-b3bf-563c-49d0d61856ed@2c3t.io> <CAKgNAkhXj=SFYSHQPnFxyZDB+r4n1_xdDo+=CUfZqXpqYmL4Cg@mail.gmail.com>
A related problem I just noticed: sysconf(3) says
| For options, typically, there is a constant
| .B _POSIX_FOO
| that may be defined in
| .IR <unistd.h> .
| If it is undefined, one should ask at run time.
| If it is defined to \-1, then the option is not supported.
But according to
<http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/unistd.h.html#tag_13_77_03_02>,
undefined is the same as defined to -1: "If a symbolic constant is not
defined or is defined with the value -1, the option is not supported
for compilation."
zw