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From: Sean Anderson <seanga2@gmail.com>
To: util-linux@vger.kernel.org, Karel Zak <kzak@redhat.com>
Cc: Mikhail Gusarov <dottedmag@dottedmag.net>,
	Matthew Harm Bekkema <id@mbekkema.name>,
	James Peach <jpeach@apache.org>,
	Sean Anderson <seanga2@gmail.com>
Subject: [PATCH 1/5] include/c: Add abs_diff macro
Date: Tue, 16 Nov 2021 21:10:34 -0500	[thread overview]
Message-ID: <20211117021038.823851-2-seanga2@gmail.com> (raw)
In-Reply-To: <20211117021038.823851-1-seanga2@gmail.com>

This macro calculates abs(a - b). It is especially useful for unsigned
numbers.

Signed-off-by: Sean Anderson <seanga2@gmail.com>
---

 include/c.h | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/include/c.h b/include/c.h
index 354b59e29..ba799d8fd 100644
--- a/include/c.h
+++ b/include/c.h
@@ -159,6 +159,14 @@
 	_max1 > _max2 ? _max1 : _max2; })
 #endif
 
+#ifndef abs_diff
+# define abs_diff(x, y) __extension__ ({        \
+	__typeof__(x) _a = (x);			\
+	__typeof__(y) _b = (y);			\
+	(void) (&_a == &_b);			\
+	_a > _b ? _a - _b : _b - _a; })
+#endif
+
 #ifndef cmp_numbers
 # define cmp_numbers(x, y) __extension__ ({	\
 	__typeof__(x) _a = (x);			\
-- 
2.33.0


  reply	other threads:[~2021-11-17  2:10 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-11-17  2:10 [PATCH 0/5] unshare: Add support for mapping ranges of user/group IDs Sean Anderson
2021-11-17  2:10 ` Sean Anderson [this message]
2021-11-17  2:10 ` [PATCH 2/5] unshare: Add waitchild helper Sean Anderson
2021-11-17  2:10 ` [PATCH 3/5] unshare: Add options to map blocks of user/group IDs Sean Anderson
2021-11-23 14:33   ` Karel Zak
2021-11-24  2:10     ` Sean Anderson
2021-11-17  2:10 ` [PATCH 4/5] unshare: Add option to automatically create user and group maps Sean Anderson
2021-11-23 14:40   ` Karel Zak
2021-11-24  2:11     ` Sean Anderson
2021-11-17  2:10 ` [PATCH 5/5] unshare: Document --map-{groups,users,auto} Sean Anderson

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